Author name code: smartt ADS astronomy entries on 2022-09-14 author:"Smartt, Raymond N." ------------------------------------------------------------------------ Title: Detection of opposite polarities in a sunspot light bridge: evidence of low-altitude magnetic reconnection Authors: Bharti, Lokesh; Rimmele, Thomas; Jain, Rajmal; Jaaffrey, S. N. A.; Smartt, R. N. Bibcode: 2007MNRAS.376.1291B Altcode: 2007astro.ph..1674B; 2007MNRAS.tmp..160B A multiwavelength photometric analysis was performed in order to study the sub-structure of a sunspot light bridge in the photosphere and the chromosphere. Active region NOAA 8350 was observed on 1998 October 8. The data consist of a 100 min time series of 2D spectral scans of the lines FeI 5576 Å, Hα 6563 Å, FeI 6302.5 Å, and continuum images at 5571 Å. We recorded line-of-sight magnetograms in 6302.5 Å. The observations were taken at the Dunn Solar Telescope at US National Solar Observatory, Sacramento Peak. We find evidence for plasma ejection from a light bridge followed by Ellerman bombs. Magnetograms of the same region reveal opposite polarity in light bridge with respect to the umbra. These facts support the notion that low-altitude magnetic reconnection can result in the magnetic cancellation as observed in the photosphere. Title: Properties of Galactic B supergiants Authors: Crowther, P. A.; Lennon, D. J.; Walborn, N. R.; Smartt, Bibcode: 2006astro.ph..6717C Altcode: Physical and wind properties of Galactic B supergiants are presented based upon non-LTE line blanketed model atmospheres, including Sher 25 toward the NGC 3603 cluster. We compare Halpha derived wind densities with recent results for SMC B supergiants and generally confirm theoretical expectations for stronger winds amongst Galactic supergiants. Mid B supergiant winds are substantially weaker than predictions from current radiatively driven wind theory, a problem which is exacerbated if winds are already clumped in the Halpha line forming region. We find that the so-called `bistability jump' at B1 (Teff ~ 21kK) from Lamers et al. is rather a more gradual downward trend. CNO elemental abundances, including Sher 25, reveal partially processed material at their surfaces. In general, these are in good agreement with evolutionary predictions for blue supergiants evolving redward accounting for rotational mixing. A few cases, including HD 152236 (zeta^1 Sco), exhibit strongly processed material which is more typical of Luminous Blue Variables. Our derived photospheric [N/O] ratio for Sher~25 agrees with that for its ejecta nebula, although a higher degree of CNO processing would be expected if the nebula originated during a red supergiant phase, as is suspected for the ring nebula ejected by the B supergiant progenitor of SN 1987A, Sk-69 202. Sher 25 has an inferred age of ~5Myr in contrast with ~2Myr for HD 97950, the ionizing cluster of NGC 3603. Sher 25 may be a foreground object or close binary evolution could be responsible for its unusual location in the H-R diagram. Title: Interpretation of Localized Deficits in Coronal Emission Authors: Zhang, Z.; Smartt, R. N.; Landman, D. A. Bibcode: 2002SoPh..207...63Z Altcode: Coronal images recorded above the limb in Fe xiv (530.3 nm) and Fe x (637.5 nm) sometimes have localized regions of anomalously low emission, with the appearance of an abrupt gap in the background corona. These `dark spaces' have been previously described in the literature in the case of the 530.3 nm line and tentatively explained by reduced coronal plasma density and/or a decrease in the line intensity due to temperatures above or below the optimal ionization temperature for Fe xiv. However, loops are sometimes observed spanning gaps, with diminished loop brightness over the region of the gap. It is concluded that at least some of these regions of reduced brightness are caused by absorption of the coronal emission. An analysis reveals that absorption by coronal ions is inadequate as a mechanism to explain the phenomenon. Absorption by neutral hydrogen is, however, consistent with the observations in terms of the reduced brightness of the gaps. The concentration of cool material in the coronal environment associated with large magnetic fields on the disk could explain the gaps. Hence, neutral hydrogen continuum absorption appears to provide a plausible interpretation of, at least, some coronal gaps. Based on this result and from measured intensities, the electron density in the region of a gap is derived and found to be consistent with estimates derived elsewhere. Title: Results from a revisit to the K2V bright points Authors: Sivaraman, K. R.; Gupta, S. S.; Livingston, W. C.; Damé, L.; Kalkofen, W.; Keller, C. U.; Smartt, R.; Hasan, S. S. Bibcode: 2000A&A...363..279S Altcode: We have used pairs of temporally simultaneous CaII K-line spectroheliograms and magnetic area scans to search for spatial correlation between the CaII K2V bright points in the interior of the network and corresponding magnetic elements. We find that about 60% of the K2V bright points spatially coincide with magnetic elements of flux density > 4 Mx cm-2. About 25% of the K2V bright points with equally enhanced emission lie over bipole elements where the fields are > 4 Mx cm-2 for both polarity elements which merge and presumably cancel and result in low fields. The rest, 15%, of the bright points coincide with areas of fields < 4 Mx cm-2 which is the noise level set by us for the magnetic scans. When magnetic elements of opposite polarity merge and form bipoles, the associated K2V bright points show excess emission. Although such excess emission is a magnetic-field-driven phenomenon, the measured value of the field at the site of the bipole is typically low, and these cases would therefore be excluded in the count of coincidences of excess emission with excess magnetic fields. In our opinion, these cases of excess emission at the sites of the bipoles, as well as at the sites of fields > 4 Mx cm-2, are both instances of magnetic-field-related emissions. If the former are not taken into account as coincidences, the correlation will drop down and this might be interpreted as not an obvious correlation. Our present results, taking into account the low fields of merging bipoles, establish the association of K2V bright points with magnetic elements. Title: Multi-wavelength observations of the 1998 September 27 flare spray Authors: Gallagher, Peter T.; Williams, David R.; Phillips, Kenneth J. H.; Mathioudakis, Mihalis; Smartt, Raymond N.; Keenan, Francis P. Bibcode: 2000SoPh..195..367G Altcode: We report on observations of a large eruptive event associated with a flare that occurred on 27 September 1998 made with the Richard B. Dunn Solar Telescope at Sacramento Peak Observatory (several wave bands including off-line-center Hα), in soft and hard X-rays (GOES and BATSE), and in several TRACE wave bands (including Fe ix/x 171 Å, Fe xii 195 Å, and C iv 1550 Å). The flare initiation is signaled by two Hα foot-point brightenings which are closely followed by a hard X-ray burst and a subsequent gradual increase in other wavelengths. The flare light curves show a complicated, three-component structure which includes two minor maxima before the main GOES class C5.2 peak after which there is a characteristic exponential decline. During the initial stages, a large spray event is observed within seconds of the hard X-ray burst which can be directly associated with a two-ribbon flare in Hα. The emission returns to pre-flare levels after about 35 min, by which time a set of bright post-flare loops have begun to form at temperatures of about 1.0-1.5 MK. Part of the flare plasma also intrudes into the penumbra of a large sunspot, generally a characteristic of very powerful flares, but the flare importance in GOES soft X-rays is in fact relatively modest. Much of the energy appears to be in the form of a second ejection which is observed in optical and ultraviolet bands, traveling out via several magnetic flux tubes from the main flare site (about 60° from Sun center) to beyond the limb. Title: SECIS: The Solar Eclipse Coronal Eclipse Imaging System Authors: Phillips, K. J. H.; Read, P. D.; Gallagher, P. T.; Keenan, F. P.; Rudawy, P.; Rompolt, B.; Berlicki, A.; Buczylko, A.; Diego, F.; Barnsley, R.; Smartt, R. N.; Pasachoff, J. M.; Babcock, B. A. Bibcode: 2000SoPh..193..259P Altcode: The Solar Eclipse Coronal Imaging System (SECIS) is an instrument designed to search for short-period modulations in the solar corona seen either during a total eclipse or with a coronagraph. The CCD cameras used in SECIS have the capability of imaging the corona at a rate of up to 70 frames a second, with the intensities in each pixel digitised in 12-bit levels. The data are captured and stored on a modified PC. With suitable optics it is thus possible to search for fast changes or short-period wave motions in the corona that will have important implications for the coronal heating mechanism. The equipment has been successfully tested using the Evans Solar Facility coronagraph at National Solar Observatory/Sacramento Peak and during the 11 August 1999 eclipse at a site in north-eastern Bulgaria. The instrument is described and preliminary results are outlined. Title: Obituary John Wainwright Evans, Jr. Authors: Dunn, Richard B.; Smartt, Raymond N.; Zirker, Jack B. Bibcode: 2000PhT....53c..94D Altcode: No abstract at ADS Title: John W. Evans died 31 October 1999. Authors: Dunn, R. B.; Simon, G. W.; Smartt, R. N.; Zirker, J. B. Bibcode: 2000SoPh..191..227D Altcode: No abstract at ADS Title: Obituary: John Wainwright Evans, 1909-1999 Authors: Dunn, Richard B.; Simon, George W.; Smartt, Raymond N.; Zirker, Jack B. Bibcode: 2000BAAS...32.1663D Altcode: No abstract at ADS Title: The Prolate Solar Chromosphere Authors: Koutchmy, S.; di Folco, E.; Auchere, F.; Baudin, F.; Delaboudinière, J. -P.; Koutchmy, O.; Noëns, J. -C.; Rondi, S.; Jimemez, R.; Smartt, R. N. Bibcode: 1999ESASP.446..385K Altcode: 1999soho....8..385K The solar prolateness above h=2Mm is now well established from measurements performed during the years of solar minimum in HeII, Hα and K3CaII lines. Low level coronal emissions usually penetrate deep enough to completely mask this effect and show CH, quite similarly to the behaviour of the HeI lines (D3; 1083nm) which does not show the prolateness. We discuss the most recent observations for 1999 given by a new facility developped at Pic du Midi Observatory (HACO II) and we compare the results with EIT results in HeII. We also brielfly discuss the possible interpretations of the prolateness effect. We favor topological effects implying a large number of nano-flares and ejecta during the interactions of small-scale low level network magnetic fields with the more static large-scale magnetic field. Title: The Solar Corona Authors: Golub, Leon; Pasachoff, Jay M.; Smartt, Raymond N. Bibcode: 1999AmJPh..67..263G Altcode: No abstract at ADS Title: Fine-Scale Structure of Coronal Loops and Consequences for Coronal Loop Interactions Authors: Kaghashvili, E.; Smartt, R. Bibcode: 1999ASPC..183..397K Altcode: 1999hrsp.conf..397K No abstract at ADS Title: SOPHIE: a solar EUV multilayer reflecting coronagraph Authors: Hassler, Donald M.; Slater, David C.; Smartt, Raymond N.; Koutchmy, Serge L. Bibcode: 1998SPIE.3443...61H Altcode: SOPHIE (Solar Photometric Helium Imaging Experiment) is a design for a new space-borne EUV multi-layer reflecting coronagraph to obtain full coronal field-of-view (solar disk and 1.1 to 3.0 solar radii above the limb) observations in He II 304 angstrom, and to measure the coronal helium abundance as a function of structure and time in the corona. Knowledge of the coronal helium abundance is fundamental to understanding the dynamics of the solar wind acceleration region, yet its value is not well known. SOPHIE will open up a new observational domain by providing full field-of-view coronagraph observations of helium, as opposed to electrons observed with traditional white light coronagraphs. Moreover, it has been recognized in the last several years that time variable phenomena is important and relevant to every aspect of the transition region and corona. Title: The prolate solar chromosphere Authors: Auchere, F.; Boulade, S.; Koutchmy, S.; Smartt, R. N.; Delaboudiniere, J. P.; Georgakilas, A.; Gurman, J. B.; Artzner, G. E. Bibcode: 1998A&A...336L..57A Altcode: We present a comparative analysis of the chromospheric solar limb prolateness, using strictly simultaneous H_alpha ground-based observations and Heriptsize{II} space-based observations. The typical prolateness is found to be Delta D/D=5.5*E(-3) in Heriptsize{II} and 1.2*E(-3) in H_alpha . The first measurements in the 30.4 nm Heriptsize{II} line over a period of two years, as well as coronal data, are discussed to explore further the origin of the prolateness and its possible consequences. Title: Advances in ground-based and space-based reflecting coronagraph designs Authors: Smartt, Raymond N.; Koutchmy, Serge L. Bibcode: 1998SPIE.3352..614S Altcode: A program to develop ground-based emission-line solar coronagraphs based on super-polished primary objective mirrors has been underway at the National Solar Observatory/Sacramento Peak over the last several years. The fundamental design requirements for effective coronagraph performance are discussed. The instrument currently under development has a 60-cm diameter objective with a 700-cm primary focal length. This design has been refined with an emphasis on achieving an extremely low level of instrumental stray light, suitable for both visible and IR operation and for carrying out high-precision polarimetry. It is seen as a possible prototype for a new generation of much larger aperture, low-scattered-light solar telescopes. Special applications include measurements of the signatures of waves in coronal loops, transient events such as coronal loop interactions, the spatial variation of magnetic fields in prominences allowing computation of electric currents, and the determination of the magnitude of coronal magnetic fields. For applications in space, a white-light reflecting coronagraph has been developed under the USAF program, SWATH (Space Weather and Terrestrial Hazards). This novel catadiopric design has a 10-cm diameter superpolished primary objective mirror, and a unique external occulter. It has a significantly higher throughput and resolution as compared with conventional space-borne lens-objective coronagraphs. Two basic modifications of this design are proposed that result in an in-line symmetric configuration, with a decrease in mass, while improving the scattered-light performance. Some special applications are described. Title: Recurrent solar wind streams Authors: Kim, I. S.; Krussanova, N. L.; Alekseeva, I. V.; Smartt, R. N. Bibcode: 1998R&QE...41...94K Altcode: A new approach to investigating the statistical relationship between certain solar features and recurrent wind streams is presented. This approach is based, on a comparative analysis of the distributions of lifetimes of a set of solar features, recurrent geomagnetic disturbances, and geomagnetic “calms.” Correlation coefficients of 0.81, 0.85, 0.79, and 0.77 are found for the distributions of several solar features—filaments, large-scale magnetic fields, coronal features, and coronal holes, respectively—and recurrent geomagnetic disturbances. A correlation factor of 0.97 between the distributions of geomagnetic “calms” and active regions is found. The combined evidence indicates that no specific type of solar feature is responsible for the recurrent stream activity. Rather, the configuration of the large-scale magnetic field of the Sun appears to control the permanently existing corpuscular activity. Since prominences trace polarity division lines of the large-scale magnetic field structure of the Sun, they have been checked as a possible general predictor of recurrent corpuscular activity; their parameters could present the most reliable indices that relate closely with trends in geomagnetic disturbances. A comparative analysis of cyclic variations of sunspot numbers, the total number of prominences, the relative number of low-height (<-20″) prominences, and recurrent geomagnetic storms is made for solar cycle N16. The relative number of low-height prominences is found to correlate broadly (0.83) with recurrent wind streams. Title: Coronal loop crossings and associated Hα activity Authors: Smartt, R. N.; Zhang, Z.; Kim, I. S.; Kaghashvili, E. Kh. Bibcode: 1998ESASP.421..333S Altcode: 1998sjcp.conf..333S No abstract at ADS Title: Observations of the Association of Prominences and the Surrounding Corona Authors: Smartt, R. N.; Zhang, Z.; Airapetian, V. S.; Kim, I. S. Bibcode: 1998ASPC..150...37S Altcode: 1998IAUCo.167...37S; 1998npsp.conf...37S No abstract at ADS Title: Analysis of the cross-sectional form of coronal loops: properties and temporal behavior. Authors: Kaghashvili, E. Kh.; Smartt, R. N. Bibcode: 1998joso.proc..110K Altcode: Observations of EUV lines provide evidence of the radial temperature dependence of coronal loops, with the highest temperature at the outer part of a loop. Here the authors investigate the cross-sectional properties of the temperature for both hot and cool loops. It is found that the radial dependence of the temperature for both types of loops has the same general characteristics, and this enables to draw some general conclusions about the thermodynamic quantities that characterize these loops. From this general picture for an idealized loop, the authors investigate its evolution for different levels of energy input, which is considered to be derived from photospheric motions of the feet of the loop. Based on this, a common scenario for coronal loop temporal behavior is described. It provides an interpretation of the difference in lifetimes of hot and cool loops and of the gradual fading of post flare coronal loops in time. Title: New missions for space-based observations of the moon, planets, and planetary systems with new all-reflecting coronagraph optics Authors: Morgan, Thomas H.; Slater, David C.; Smartt, Raymond N. Bibcode: 1997SPIE.3116...27M Altcode: Creative new optical designs for coronagraphs which use only reflecting elements are extremely well suited for planetary studies which usually require detection of large, faint, tenuous sources about bright central planets (themselves worthy of study). These new coronagraphic designs not only allow the observation of extended atmospheres and coronae, they also allow critical observations of the central planet at the same time with instruments optimized for different wavelengths. The new coronagraphic systems can be more easily accommodated within the envelope of launch vehicle capabilities available today than can older, slower systems, and they permit simple spacecraft designs which reduce weight, power, and cost. They possess inherently higher end-to-end optical efficiencies. The very modest fluxes associated with many extended sources in the solar system, however, require state-of-the-art fabrication techniques, and place new demands on focal plane instrumentation. We focus here on an instrument designed to observe the lunar atmosphere. Also considered are several archetypical problems, including the study of the neutral cloud an ionized torus associated with Jupiter's moon Io and of comets. Title: Imaging Coronal Emission Lines under High Sky-Background Conditions Authors: Keller, C. U.; Smartt, R. N. Bibcode: 1996SoPh..166..311K Altcode: We have obtained images in solar coronal emission lines under high sky-background conditions by making precise differential measurements between the coronal emission line and the near-by continuum, which is primarily due to scattered light from the solar disk. Chopping between the two wavelengths was performed at 100 kHz to avoid artifacts from fast-flying dust particles and other aerosols, and also from seeing effects. The differential signal was detected with a novel CCD camera that demodulates signals up to 100 kHz. These preliminary observations show coronal emission at the 0.2% level of the scattered-light background and pave the way to efficient and precise imaging of coronal emission features under less than ideal `coronal-sky' conditions. Title: Solar drivers of the interplanetary and terrestrial disturbances Authors: Balasubramaniam, K. S.; Keil, Stephen L.; Smartt, Raymond N. Bibcode: 1996ASPC...95.....B Altcode: 1996sdit.conf.....B No abstract at ADS Title: White-Light Reflecting Corona graph for the SWATH Mission Authors: Smartt, Raymond N.; Dunn, Richard B.; Carmichael, Roger B.; Gregory, B. Scott; Plum, Douglas W.; Neidig, Donald F.; Golub, Leon; Bookbinder, Jay A.; Koutchmy, George U.; Nystrom, Serge L.; Zimmermann, Jean-Paul Bibcode: 1996ASPC...95..531S Altcode: 1996sdit.conf..531S No abstract at ADS Title: Coronal Loop Interactions Observed in Optical Emission Lines Authors: Smartt, R. N.; Airapetian, V. S.; Zhang, Z. Bibcode: 1996mpsa.conf..531S Altcode: 1996IAUCo.153..531S No abstract at ADS Title: Optical Diagnostics of Coronal Loop Interactions Authors: Airapetian, Vladimir S.; Smartt, Raymond N. Bibcode: 1995ApJ...445..489A Altcode: Coronal loop interactions (CLIs) are commonly observed in images of postflare loop systems recorded in the 5303 A (Fe XIV) and 6374.5 A (Fe X) lines. The CLIs appear as occasional transient brightenings at the projected intersections of adjacent loops. Observational parameters of a CLI of 1981 December 7 are used to determine values of key plasma quantities that characterize these events, leading to optical diagnostics. On the basis of this analysis, the likelihood of detecting CLIs at other coronal-line wavelengths is estimated. Finally, the possible contribution of CLIs to coronal heating is investigated in terms of the estimated frequency of binary loop-loop collisions in the solar corona and their dependence on available photospheric magnetic flux, within and outside active regions. Possible implications for heating of coronae of dMe stars are discussed. Title: Magnetic Reconnection Model for X-Ray Flare Loop Interaction Authors: Zhang, Zhen-Da; Li, Xiao-Qing; Smartt, R. N. Bibcode: 1995Ap&SS.226...31Z Altcode: The subtle interactions between the magnetohydrodynamics (MHD) and transverse plasmons are investigated. It is shown that there is a resistive instability by the plasmon's soliton in a current sheet, which eventually turns into an eruptive instability at the magnetic field reconnection. In the case of ion-acoustic turbulence, the high temperature current sheet model must adopt the aromalous conductivity instead of the Coulomb conductivity. The numerical results are consistent with the observations obtained by Hanaoka (1994). Thus the flare caused by X-ray loop coalescence can be basically interpreted by this model of magnetic field reconnection driven by ponderomotive force. Title: CLEAR : A Concept for a "Coronagraph and Low Emissivity Astronomical Reflector" for Solar and Nighttime Observations Authors: Beckers, J. M.; Kuhn, J.; Neidig, D.; Rabin, R.; Rimmele, T.; Smartt, R. N. Bibcode: 1995SPD....26..722B Altcode: 1995BAAS...27..971B No abstract at ADS Title: Emission-Line Signatures of Coronal Loop Interactions Authors: Airapetian, V. S.; Smartt, R. N. Bibcode: 1995itsa.conf...31A Altcode: No abstract at ADS Title: Near-Infrared Coronagraphic Detection of Space Debris Authors: Neidig, D. F.; Smartt, R. N.; Kim, I. S.; Koutchmy, S. Bibcode: 1995itsa.conf..253N Altcode: No abstract at ADS Title: Mirror Coronagraphic Device and Its Application Authors: Kim, I. S.; Bougaenko, O. I.; Brouevitch, V. V.; Koutchmy, S.; Neidig, D. F.; Smartt, R. N.; Evseev, O. A. Bibcode: 1995itsa.conf..239K Altcode: No abstract at ADS Title: Reflecting Coronagraphs: Prospects Authors: Smartt, R. N.; Koutchmy, S. Bibcode: 1995itsa.conf..163S Altcode: No abstract at ADS Title: Comments on Doppler shifts deduced by the Fabry-Perot technique Authors: Kim, I. S.; Alexeeva, Irina V.; Smartt, Raymond N. Bibcode: 1994ESASP.373...71K Altcode: 1994soho....3...71K No abstract at ADS Title: Photometric imaging observations of the emission corona Authors: Altrock, R. C.; Smartt, R. N. Bibcode: 1994ESASP.373..425A Altcode: 1994soho....3..425A No abstract at ADS Title: Progress in dynamic research of solar flare magnetic loops. Authors: Zhang, Zhenda; Smartt, R. N. Bibcode: 1994PABei..12..287Z Altcode: No abstract at ADS Title: Role of loop-loop encounters in coronal heating Authors: Airapetian, V. S.; Smartt, R. N. Bibcode: 1994ESASP.373...29A Altcode: 1994soho....3...29A No abstract at ADS Title: Magnetic reconnection theory for coronal loop interaction. Authors: Li, X. -Q.; Zhang, Z.; Smartt, R. N. Bibcode: 1994A&A...290..963L Altcode: Images of post-flare loop systems recorded in coronal green- and red-line emissions display occasional transient enhancements at the intersection of some loops where they come into contact. Such enhancements are investigated in terms of the likely plasma processes involved in these dynamic events. For this, the interaction between magnetohydrodynamic and high frequency plasma waves, and the instability associated with an electromagnetic solitary wave in a current sheet, are studied. It is shown that there is a resistive instability, which eventually turns into an eruptive instability at the onset of magnetic field reconnection. The numerical results are consistent with the observations. Thus the phenomenon of occasional enhancements in the vicinity of the projected intersection of two loops may be basically interpreted by this theory of magnetic field reconnection driven by ponderomotive force. Title: Moon-based UV reflecting coronagraph Authors: Vial, J. C.; Koutchmy, S.; Smartt, R. N. Bibcode: 1994AdSpR..14f..43V Altcode: 1994AdSpR..14...43V UV observations of the solar disc, and above the limb, have evidenced a wide range of possible diagnostics, especially in the Lα line. On the disc, Lα traces the magnetic (sometimes unexpected) structuring of the top of the atmosphere; out from the limb, it allows measurement of radial velocities up to a few solar radii where most optical techniques fail. Other diagnostics include the kinematics of ejections (e.g. CMEs, but also small-scale rapidly evolving plasmoïds). We propose a dual-channel reflecting coronagraph combining relatively-high angular resolution (0.2-0.4'') with large spatial (2.5 solar radii from Sun center) and temporal coverage. The advantages offered by a Moon-based instrument are discussed. Title: Analysis of loop interaction in the visible emission corona Authors: Zhang, Z.; Li, X. -Q.; Smartt, R. N. Bibcode: 1994AdSpR..14d..41Z Altcode: 1994AdSpR..14...41Z Images of coronal post-flare loop systems in the two coronal lines, 5303Å(Fe XIV) and 6374Å(FeX), show occasional brightenings at projected points of intersection of overlapping loops. Such brightenings are interpreted as an interaction between two loops coming into localized contact due to motion of loop footpoints or when one loop grows more rapidly than a higher loop. The observations indicate that partial magnetic reconnection occurs, with associated heating and subsequent cooling of the plasma in the interaction region. The phenomenon is commonly observed in post-flare loop systems. Low-energy events apparently occur also, with less frequency, in quiet coronal loop systems. An analysis suggests that these events can, as observed, be described by an initial resistive instability in the region of the enhancement, which eventually turns into an eruptive instability at the onset of reconnection. The energy contribution of these small events to the overall coronal environment is estimated. Title: Coronal Loop Interaction Observed at Visible Wavelengths Authors: Smartt, R. N.; Zhang, Z.; Kim, I. S.; Reardon, K. P. Bibcode: 1994scs..conf..219S Altcode: 1994IAUCo.144..219S Brightening is observed to occur in regions where two loops come into contact, with resultant heating of the common plasma volume, and subsequent cooling. The observations show systematically that a brightness maximum in the cooler (634 Å) line lags that of the hotter (5303 Å) line. Coalescence is evident in that the brightness can extend away from the overlapping region along the adjacent parts of the loops. Title: Near-IR Solar Coronal Observations with New-Technology Reflecting Coronagraplis Authors: Smartt, R. N.; Koutchmy, S.; Noens, J. -C. Bibcode: 1994IAUS..154..603S Altcode: No abstract at ADS Title: IR Observations of the K and F Corona During the 1991 Eclipse Authors: Kuhn, J. R.; Lin, H.; Lamy, P.; Koutchmy, S.; Smartt, R. N. Bibcode: 1994IAUS..154..185K Altcode: No abstract at ADS Title: On the Eclipse E-Corona Observations by the Fabry-Perot Technique Authors: Kim, I. S.; Smartt, R. N. Bibcode: 1994scs..conf..549K Altcode: 1994IAUCo.144..549K Interpretations of the eclipse Fabry-Perot interferograms obtained by different authors are compared particularly in point of view of velocity measurements. Advantages and disadvantages of the instrumentation consisting of a Fabry-Perot etalon and a narrow band interference filter are discussed when a coronal emission is imposed on steep gradient coronal continuum. A list of optical and near infrared emission coronal lines is analyzed and a recommendation for employment of the Fe XIV (5303 Å) and Fe XI (7892 Å) is given. Title: The SWATH Satellite Program Authors: Bookbinder, J.; Golub, L.; Deluca, E.; Smartt, R. Bibcode: 1993AAS...183.0810B Altcode: 1993BAAS...25R1302B No abstract at ADS Title: Post-Flare Coronal Loop Interaction Authors: Smartt, R. N.; Zhang, Z.; Smutko, M. F. Bibcode: 1993SoPh..148..139S Altcode: High-resolution images of post-flare loop systems in FeXIV (5303 å) and FeX (6374 å) display occasional transient enhancements at the projected intersection of some loops. The brightness of a green-line enhancement gradually increases to a marked maximum and then fades with a lifetime of the order of thirty minutes. The red-line image at the same location, although fainter, shows the same overall characteristics, its maximum following that of the green-line on average by 8.6 min. Hα then becomes more evident and reaches a maximum in extent on average 9.3 min after the red-line maximum. The phenomenon is interpreted as a process of localized loop coalescence involving partial magnetic reconnection. Estimates of the electron density are derived from the cooling time following the initial heating of the plasma in the immediate vicinity of the X-point of interaction. Similar estimates for the energy dissipated, equivalent to a very small flare, are derived by two independent methods. Title: Coronal Loop Interaction Authors: Smartt, R. N.; Zhang, Z. Bibcode: 1993ASSL..183..183S Altcode: 1993pssc.symp..183S No abstract at ADS Title: Morphology of coronal loop interactions. Authors: Smartt, Raymond N.; Zhang, Zhenda Bibcode: 1992ESASP.348..185S Altcode: 1992cscl.work..185S Localized transient brightenings appear occasionally in images of post-flare coronal loop systems, as recorded in the 5303 Å (Fe XIV) and 6374 Å (Fe X) lines. Such brightenings occur apparently also in quiet coronal loop systems, but only in the lower range of energies that characterize these events. Brightenings result when two loops come into contact at some point, the enhancement typically extending partially along the loops away from the point of intersection. The observations show systematically that a brightness maximum in the cooler (6374 Å) line lags that of the hotter (5303 Å) line by about 9 min, on average, while Hα material appears about 9 min later, the sequence revealing cooling of the plasma following initial heating. Since an enhancement does not appear in the red line prior to a corresponding maximum occurring in the green line, it appears that the plasma is heated rapidly during initial coalescence. Hence, on this basis it is inferred that such events should be observable in higher-temperature lines prior to a maximum appearing in the green line. Hα material is seen to stream down to the surface from the site of interaction, but there is some evidence also of material moving up from the surface to the region of interaction. The typical morphology of these events is discussed. Title: No Evidence of a Circumsolar Dust Ring from Infrared Observations of the 1991 Solar Eclipse Authors: Lamy, P.; Kuhn, J. R.; Lin, H.; Koutchmy, S.; Smartt, R. N. Bibcode: 1992Sci...257.1377L Altcode: During the past 25 years there have been many attempts to detect a possible dust ring around the sun, with contradictory results. Before the 1991 eclipse, infrared eclipse experiments used single-element detectors to scan the corona along the ecliptic for excess surface brightness peaks. The availability of relatively large-format infrared array detectors now provides a considerable observational advantage: two-dimensional mapping of the brightness and polarization of the corona with high photometric precision. The 1991 eclipse path included the high-altitude Mauna Kea Observatory, a further advantage to measure the corona out to large angular distances from the sun. Results are reported from an experiment conducted on Mauna Kea with a HgCdTe-array detector sensitive to wavelengths between 1 and 2.5 micrometers, using broad-band J, H, and K filters. Although the sky conditions were not ideal, the H- and K-band surface brightnesses clearly show the inhomogeneous structure in the K-corona and the elliptical flattening of the F-corona, but no evidence of a circumsolar, local dust component out to 15 solar radii. Title: Development of Reflecting Coronagraphs Authors: Smartt, R. N.; Koutchmy, S. Bibcode: 1992ASPC...26..660S Altcode: 1992csss....7..660S No abstract at ADS Title: Some considerations for instrumentation for a lunar-based solar observatory Authors: Smartt, Raymond N. Bibcode: 1992ecos.proc.1890S Altcode: Outstanding problems in solar physics and observational trends and directions of instrumental development in solar astronomy are discussed briefly. These lead to the specification of observational opportunities and corresponding instrumentation for lunar-based solar observing facilities. First and second phases for a lunar-based solar observatory are considered. For phase I, an automated, compact Lyman-alpha/CIV telescope/coronagraph used principally to monitor flare activity on the solar disk as well as coronal disturbances is proposed. For phase II, three facilities are proposed: an array of medium-aperture, extremely low-instrumental-scatter telescopes operating from EUV through IR wavelengths; X-ray, XUV telescopes of high-angular resolution; and a hard X-ray, gamma-ray facility. Dual-purpose (daytime/nighttime) operation is emphasized. Title: Interpretation of Coronal Loop Interactions Authors: Smartt, R. N.; Li, X. -Q.; Zhang, Z. Bibcode: 1992AAS...179.3806S Altcode: 1992BAAS...24..681S No abstract at ADS Title: Interaction of Coronal Loops Authors: Zhang, Z.; Smartt, R. N. Bibcode: 1992AcASn..32..233Z Altcode: No abstract at ADS Title: The morphological characteristics and cooling mechanisms of the post-flare loop system of April 28, 1980 Authors: Lin, J.; Zhang, Z.; Wang, Z.; Smartt, R. N. Bibcode: 1992A&A...253..557L Altcode: The paper describes the morphology and evolution of the postflare loop system of April 28, 1980, which were obtained with the 40-cm coronograph at NSO/Sacramento Peak (USA). It was found that this flare loop system is still in variation during the stage of main phase; mass and energy in the loops are in dynamic equilibrium. The cooling time for a single loop was estimated on the basis of losses due to radiation, thermal conduction, and adiabatic expansion of plasma in the loop. The results show that radiative cooling dominates conductive and expansion cooling in the cool (T about 10 exp 4 K) flare loops. The nature of the likely resources which permit the loops to stay bright for a long time is discussed. Title: Interaction of coronal loops Authors: Zhang, Zhen-Da; Smartt, R. N. Bibcode: 1991AcASn..32..233Z Altcode: In this paper the occasional transient enhancement at the interaction regions of some loops as recorded in coronal images of FeXIV (5303A) and FeX (6374A), and the associated images in H alpha have been analyzed. The brightness of a green line enhancement gradually increases to a maximum and then fades with a typical lifetime of about 20-30 minutes. The maximum of the red line enhancement at the same location follows that of the green line on average by 8.6 minutes, and H alpha then reaches a maximum in extent on average 9.3 minutes after the red line maximum. This phenomenon is interpreted as a process of localized magnetic reconnection. Estimates of the electron density are derived from the cooling time, and the values of dissipated energy are obtained by two separate methods. Title: Eclipse Plans for NSO/SP Authors: Zirker, J. B.; Koutchmy, S.; Coulter, R. L.; November, L. J.; Smartt, R. N. Bibcode: 1991BAAS...23.1063Z Altcode: No abstract at ADS Title: Dark Gaps in Emission Corona Images Authors: Smartt, R. N.; Zhang, Z.; Landman, D. A. Bibcode: 1991BAAS...23Q1045S Altcode: No abstract at ADS Title: High resolution telescopes at the National Solar Observatory Authors: Dunn, R. B.; Smartt, R. N. Bibcode: 1991AdSpR..11e.139D Altcode: 1991AdSpR..11..139D The principal high-resolution telescopes of the National Solar Observatory are its two evacuated telescopes of 61-cm aperture (Kitt Peak) and 75-cm aperture (Sac Peak). The 61-cm telescope is used for making full-disk magnetograms, spectromagnetograms and λ10830 maps that show coronal holes, and is dedicated to synoptic programs. We describe the 75-cm telescope at Sac Peak. Upgrades that are underway include an adaptive mirror and fast mirror system that will feed several focal-plane instruments including the Universal Spectrograph, a new spectrograph whose detectors are CCD cameras, the Universal Birefringent Filter, a Fabry-Perot Interferometer and an Advanced Stokes Polarimeter (ASP), is being constructed at the High Altitude Observatory. Additional equipment planned for this telescope includes an improved temperature control subsystem for the entrance window, an instrument that continually measures Fried's parameter, r0, and integrating more advanced data collection systems into a computer network. The observatory is also pursuing a mirror coronagraph, which should have high resolution and which could be built in apertures larger than a meter.

Operated by the Association of Universities for Research in Astronomy, Inc. (AURA) under cooperative agreement with the National Science Foundation. Title: Interpretation of polarization measurements of coronal Fe XIII (10747 Å) emission. Authors: Smartt, R. N.; Querfeld, C. W. Bibcode: 1991sopo.work..326S Altcode: Measurements of the linear polarization of Fe XIII (10747 Å) coronal emission are discussed. Polarization maps appear to be consistent with the general form of the expected magnetic field distribution in the corona as projected in the plane of the sky. Well-defined, large-scale coronal structures are found to be mapped well by corresponding polarization measurements. Title: The Morphology Evolution of the Cool Post-Flare Loop System of April 28, 1980 Authors: Lin, J.; Zhang, Z.; Wang, Z.; Smartt, R. N. Bibcode: 1990AcASn..31..313L Altcode: 1990AcASn..31..317L No abstract at ADS Title: UV solar reflecting coronagraph Authors: Smartt, R. N.; Koutchmy, S.; Vial, J. C. Bibcode: 1990AIPC..207..578S Altcode: 1990am...proc..578S A dual-channel reflecting coronagraph is proposed that would provide observations of Lα corona and chromosphere, upper transition-region phenomena in CIV, and also helioseismology observations in the continuum around 166 nm. Each channel would use a 104×104-UV-sensitive CCD array. The combined velocity and magnetic field data would link events in the chromosphere, the transition region and the corona to an elongation of about 2.5 R0. These data would be used to study both the global-scale and also the fine-scale properties of the corona in terms of the physical processes that deposit energy and momentum in the corona. Specific question to be investigated would be the origin and morphology of CME's and other coronal transients, sources of coronal heating, and the source(s) and dynamics of the coronal wind in the inner coronal region. Title: Real-time image processing and data handling for ground-based and spaceborne coronal observations Authors: Koutchmy, S.; Colley, S.; Smartt, R.; Nitschelm, C.; Zimmermann, J. P. Bibcode: 1990SPIE.1235..849K Altcode: Ground-based observations of the solar corona, as well as deep night-time observations close to bright objects, are degraded by highly variable aureole effects produced by the earth's atmosphere, even when the stationary background pattern of both atmospheric and instrumental origin is removed using detectors and special processing techniques. First observations using an objective mirror advanced coronagraph reveal that small particles (both continental and maritime aerosols) imaged on the focal plane as they cross the field of view can dominate the background unter clear-sky conditions, producting a considerable noise background that it is not easily removed. Suggestions are made to reduce to noise of this "dynamical aureole". The authors also discuss the possibility of optically detecting orbital space debris of small size, using either an externally-occulted space-borne mirror coronagraph or a large-aperture ground-based mirror coronagraph, and the corresponding detection system requirements. Title: New technology mirror coronagraph with extended applications Authors: Smartt, Raymond N.; Koutchmy, Serge L.; Colley, Stephen A.; Caron, R.; Schwenn, Rainer; Restaino, Sergio R. Bibcode: 1990SPIE.1236..206S Altcode: General design considerations of objective-mirror coronagraphs are presented. A 1-m-focal-length prototype reflecting coronagraph based on a 5.5-cm aperture spherical superpolished silicon mirror objective is described. The design is simple off-axis reflection from the objective to a conventional coronagraph optical system (occulting disk, field lens, Lyot stop, and imaging system). This instrument has produced the first images of the emission corona using a ground-based reflecting coronagraph. A second prototype instrument based on a 15-cm aperture superpolished fused-silica mirror is also described. Title: Interacting Coronal Loops Authors: Smartt, R. N.; Zhang, Z. Bibcode: 1990BAAS...22R.870S Altcode: No abstract at ADS Title: Coronal Loop Interaction Authors: Smartt, R. N.; Zhang, Z. Bibcode: 1990IAUS..142..350S Altcode: No abstract at ADS Title: Measurement of telescope system aberrations Authors: Smartt, R. N. Bibcode: 1989hsrs.conf..232S Altcode: No abstract at ADS Title: High resolution observations of the solar corona: why and how? Authors: Koutchmy, S.; Smartt, R. N. Bibcode: 1989hsrs.conf..560K Altcode: No abstract at ADS Title: Ground-Based Mirror Coronograph: First Results Authors: Smartt, R. N.; Koutchmy, S.; Schwenn, R. Bibcode: 1989BAAS...21..848S Altcode: No abstract at ADS Title: Image processing of coronal pictures Authors: Smartt, Raymond N.; Koutchmy, Olga; Koutchmy, Serge; Nitschelm, Christian; Sykora, Julius Bibcode: 1989STIN...8924252S Altcode: Coronal images contain many complex, superposed, faint, optically-thin structures: rays, loops, curved streamers, etc. The spatial resolution is often limited by the signal/noise ratio in the recording medium while the dynamic range in intensity is severely dominated by the radial gradient. The results obtained with a new simple image processing algorithm are applied to several typical eclipse and coronographic pictures. This 2D filter (second order difference operator in k-direction) shows superior quality by improving the signal/noise ratio, reducing the dynamic range and enhancing faint coronal structures. A comparison with results obtained with more commonly used 2D filters is also presented. The algorithm used here are briefly described, together with discussions of enhanced coronal images of coronal physics interest. Title: The Plasma Property of Cool Flare Loops of 1980APR28 Authors: Lin, J.; Wang, Z. Y.; Zhang, Z. D.; Smartt, R. N. Bibcode: 1989AcASn..30...52L Altcode: No abstract at ADS Title: Lithium niobate double channel Fabry-Perot interferometer for solar corona uses Authors: Bonaccini, Domenico; Smartt, Raymond N. Bibcode: 1988ApOpt..27.5095B Altcode: The use of a tunnable etalon in the measurement of spectral profiles of solar corona emission lines is investigated. The etalon is a y-cut plate of lithium niobate. A suitable tunning range for the line is + or - 1 A corresponding to an applied voltage of + or - 1000 V for a thickness of 0.1 mm. A passband of 0.2 A can realistically be obtained with an appropriate free spectral range of 6 A. Thermal analysis shows that a temperature excursion of 0.05 C corresponds to a spectral drift of less than 0.05 FWHM. An emission line profile is obtained by scanning an ordinary-ray passband through the emission line, while measuring the difference between this signal and that from and adjacent extraordinary-ray passband. Using polarization chopping, the scattered-light component due to the sky and instrument is efficiently removed. The extraordinary-ray (reference) passband is insensitive to the applied voltage; hence the reference signal is substantially unaffectted by the spectral modulation in the scattered light due to the solar absorption spectrum. Title: The GONG instrument. Authors: Harvey, J.; Abdel-Gawad, K.; Ball, W.; Boxum, B.; Bull, F.; Cole, J.; Cole, L.; Colley, S.; Dowdney, K.; Drake, R.; Dunn, R.; Duvall, T.; Farris, D.; Green, A.; Hartlmeier, R.; Harvey, J.; Hubbard, R.; Jackson, P.; Kucera, D.; Miller, C.; Miller, D.; Petri, A.; Poczulp, G.; Schwitters, J.; Simmons, J.; Smartt, R.; Streander, G.; Vaughn, F.; Wiborg, P.; GONG Instrument Development Team Bibcode: 1988ESASP.286..203H Altcode: 1988ssls.rept..203H An instrument is being developed to provide high-quality Doppler oscillation measurements for the Global Oscillation Network Group (GONG) project. This instrument uses the Fourier tachometer principle of sweeping a squared-cosine transmission function across a limited region of the solar spectrum centered on the Ni I line at 676.8 nm. Doppler shift is detected as a phase shift between the modulated solar signal and a simultaneously modulated signal from a stabilized laser. The solar signal is measured with an array of about 250 by 250 pixels covering the full disk. Design goals include a short-term noise level at a single pixel of about 10 m/s per integration interval of 60 s and a long-term stability of better than one m/s. A "breadboard" model has been in operation since early 1988 and a prototype is under construction. Most of the observations as of August 1988 have been of the Doppler shift of the entire sun imaged onto a single detector. These observations easily show the global p-mode oscillations with good short-term signal-to-noise ratio but have revealed a number of interesting problems. Imaging measurements have started with promising results. Title: Spectroscopic Coronal Observations Using A High-Sensitivity Camera Authors: Smartt, R. N.; Colley, S. A.; Gilliam, L. B.; Koutchmy, S.; Zirker, J. B. Bibcode: 1988BAAS...20..704S Altcode: No abstract at ADS Title: Image processing of coronal pictures. Authors: Koutchmy, Olga; Koutchmy, Serge; Nitschelm, Christian; Sykora, Julius; Smartt, Raymond N. Bibcode: 1988sscd.conf..256K Altcode: The authors present the results obtained with a new simple image processing algorithm applied to several typical eclipse and coronographic pictures. This 2D filter (second order difference operator in k-direction) shows superior quality by improving the signal/noise ratio, reducing the dynamic range and enhancing faint coronal structures. A comparison with results obtained with more commonly used 2D filters is also presented. The authors describe briefly the algorithm used, together with discussions of enhanced coronal images of coronal physics interest. Title: Coronal emission-line polarization. Authors: Smartt, Raymond N.; Arnaud, Jean Bibcode: 1988sscd.conf..451S Altcode: Polarization measurements from two large data sets are discussed. The first set consists of measurements obtained in the 5303 Å line of Fe XIV with the Pic du Midi Coronameter, at heights ranging from 1.1 Rsun to 2.0 Rsun from disk center. The second set consists of similar observations in the 10747 Å line obtained with the HAO/SPO Coronal Emission-Line Polarimeter, from 1.1 Rsun to 1.8 Rsun. Both of the polarization vectors are close to radial with a mean magnitude of 0.016 and 0.12, respectively. Comparison of these data with NSO/SP coronal images in the 5303 Å line confirms that the vectors trace out the coronal loop systems in cases where such systems are well-defined. For both sets of observations, the magnitude of the measured polarization is much less than that predicted from simple scattering theory. The discrepancy is discussed in terms of the various mechanisms and special geometries that can account for it. Title: Day-time seeing statistics at Sacramento Peak Observatory Authors: Brandt, P. N.; Mauter, H. A.; Smartt, R. Bibcode: 1987A&A...188..163B Altcode: A method for the photoelectric measurement of angle-of-arrival fluctuations at the solar limb is described, from which Fried's seeing parameter r0 can be determined. From a set of 2092 measurements, each of 10 s duration, performed on 146 observing days in the period from June 84 to September 86 at the solar vacuum tower telescope of the Sacramento Peak Observatory, a log-normal distribution of the r0 values gave a median r0 = 8.7 cm (measured at λ = 510 nm), with a standard deviation σ = 0.25 in logarithmic units. The results are compared with atmospheric sounding experiment data and longterm day- and night-time seeing statistics obtained at other observatories. Title: High Spatial Resolution Coronal Physics: The Need for Larger Coronagraphs Authors: Smartt, R. N.; Koutchmy, S.; Zirker, J. P. Bibcode: 1987BAAS...19Q1122S Altcode: No abstract at ADS Title: Loop interaction in the visible emission corona - morphological details. Authors: Smartt, Raymond N.; Zhang, Zhenda Bibcode: 1987NASCP2483..129S Altcode: 1987tphr.conf..129S Coronagraph observations of two post-flare loop systems, recorded photographically in the emissions of Fe XIV (5303 Å) and Fe X (6374 Å), show occasional enhancements at the intersections of some loops. The brightness of such enhancements in the green-line gradually increases to a maximum value several times greater than that of the legs of the loops and then declines with a typical lifetime ≡30 - 60 minutes. In red-line emission the loop systems are usually very faint, but show the same overall type of enhancement, with a lag in maximum brightness relative to that of the green line ≡10 minutes. The electron density, derived from the cooling times, is ≡1012cm-3. Title: Near-Infrared Measurements of the Radiance of the Solar Corona Authors: Smartt, R. Bibcode: 1987BAAS...19..924S Altcode: No abstract at ADS Title: Flare Associated Coronal Loop Systems in Fexiv 5303A Fex 6374 and Hα Morphological Details and Derived Parameters Authors: Jain, R.; Smartt, R. N.; Zhaug, Z. Bibcode: 1987BASI...15...19J Altcode: No abstract at ADS Title: Day-time seeing statistics at Sacramento Peak Observatory. Authors: Brandt, P. N.; Mauter, H. A.; Smartt, R. Bibcode: 1987LFTR...26...41B Altcode: The results of the extended series of day-time seeing measurements performed at the vacuum tower telescope of Sacramento Peak show that the median r0 value of 8.7 cm is about a factor of 2 higher than measured at other mountain sites during day-time. Even without correction for zenith distance this median value ranks among the highest measured in longterm night-time tests at observatories like Kitt Peak, Flagstaff, Chile, Calar Alto (Spain), Roque de los Muchachos (Canary Islands) and others - although one should be cautious when comparing results obtained with different measuring techniques. Title: Mass Estimate of an Erupting Loop Prominence Authors: Smartt, R. N. Bibcode: 1986BAAS...18..899S Altcode: No abstract at ADS Title: Electric Field Measurements in Solar Flares Authors: Zhang, Z.; Smartt, R. N. Bibcode: 1986SoPh..105..355Z Altcode: Meaurements of solar flare spectra have allowed the electric field strengths in two flares to be determined, using the Inglis-Teller formula. Further, an independently estimated value for the electron density has allowed the two components of this field, that is, the interionic component and the external component that arises, for example, through plasma instabilities, to be separately extracted. External electric field strengths ∼0.5 kV cm−1 for a limb flare and ∼1.3 kV cm−1 for a white-light flare are found. Estimates of electric fields strengths generated by the resistive magnetic tearing instability indicate that this process could account for a significant part of the electric field if pre-existing magnetic field strengths in the flaring regions are characterized by a few kilogauss. Other plasma processes probably contribute measurably as well. Title: Coronal Loop Interaction in the Post-Flare Phase Authors: Smartt, R. N.; Zhang, Z. Bibcode: 1986BAAS...18..699S Altcode: No abstract at ADS Title: Zone-plate Radial-shear Interferometers a Study of Possible Configurations Authors: Smartt, R. N.; Hariharan, P. Bibcode: 1985AcOpt..32.1475S Altcode: 1985JMOp...32.1475S No abstract at ADS Title: Point-diffraction interference microscopy Authors: Smartt, Raymond N.; Steel, W. H. Bibcode: 1985ApOpt..24.1402S Altcode: No abstract at ADS Title: Vector Magnetic Fields in Prominences - Part Two Hei d3 Stokes Profiles Analysis for Two Quiescent Prominences Authors: Querfeld, C. W.; Smartt, R. N.; Bommier, V.; Landi Degl'Innocenti, E.; House, L. L. Bibcode: 1985SoPh...96..277Q Altcode: The Stokes components of He I D3 emission in two quiescent prominences, using full spectral profile measurements, are analyzed to derive vector magnetic fields. Two independently developed schemes, based on the Hanle effect, are used for interpretation. They involve solutions of the statistical equilibrium equations for the He I D3 multiplet, including the effect of coherency and full level crossing, which predict the magnetic field dependence of the observed polarization. Derived magnetic field vector solutions for each pair of linear polarization Stokes profiles corresponding to an observational point in the prominence are, intrinsically, not uniquely determined, and a set of possible solutions is usually obtained. However, mutual consistency of these solutions with those independently predicted by the form of the circular polarized component, allow, in almost all cases, rejection of all solutions of a set except one symmetrical pair. Of such a pair, a unique solution can be determined with a high confidence level by reference to independent potential field information. Field vectors are found usually to be close to horizontal and normal to the prominence surface, but extreme exceptions are found. Field values range from 6 G to 60 G. The derived vectorfield configurations and their magnitudes are briefly discussed relative to these prominences and to different quiescent prominence models. Title: Detailed Morphology of Flare-Associated Coronal Loops Authors: Smartt, R. N.; Jain, R. Bibcode: 1985BAAS...17Q.645S Altcode: No abstract at ADS Title: Comparison of Coronal Emission Line Structure and Polarization Authors: Querfeld, C. W.; Smartt, R. N. Bibcode: 1984SoPh...91..299Q Altcode: Simultaneous observations obtained with the HAO/SPO coronal emission-line polarimeter and the new SPO emission-line coronagraph are compared. The polarimeter data are measured in the FeXIII (10747 Å) line and the coronagraph observations are recorded in the FeXIV (5303 Å) line. The polarimeter field-of-view is relatively coarse compared with the resolution limit of the coronagraph. Therefore, the observed coronal polarization cannot be related directly to the detailed loop structures that characterize the localized coronal distribution, but it is found that large-scale emission features have corresponding polarization signatures. Since the measured linear polarization vectors describe the projected magnetic field direction, as shown theoretically, it follows that the form of the large-scale coronal distribution describes corresponding magnetic field structures. Measured polarization values are consistent with those predicted theoretically. Interpretation of these data to obtain corresponding magnetic field directions suggests that the value usually accepted for iron abundance in the corona might be too large. Title: Visible Coronal Emission Associated with a Quiescent Prominence Authors: Smartt, R. N.; Zhang, Z. Bibcode: 1984SoPh...90..315S Altcode: Emission-line coronagraph images of a high-latitude, nominally quiescent prominence, recorded at wavelengths of Hα, 6374 Å (Fex) and 5303 Å (Fe XIV), are analyzed. Over a two-day period, the coronal images, which are found to arise predominantly from coronal emission, evolve such that the emission becomes concentrated at locations corresponding to the outer regions of the prominence. This edge enhancement has similar characteristics to results inferred from EUV prominence observations. It is postulated that this coronal emission associated with the prominence results from MHD wave dissipation. Dissipation lengths for slow-mode, fast-mode and Alfvén waves are estimated for different prominence conditions. Of these, fast-mode waves appear to be the most physically realistic heating source if the prominence magnetic field is along the length of the prominence. Title: Vector Magnetic Fields in Prominences: Observations and Analysis Authors: Smartt, R. N.; House, L. L. Bibcode: 1984KodOB...4...35S Altcode: Stokes polarimeter spectral profiles of He I D3, representing many observational points within a quiescent prominence, are interpreted using a detailed quantum-mechanical theory of resonance polarization for the D3 multiplet. The multiple set of solutions obtained when the linear polarization information alone is used can be reduced, generally to a symmetric pair, when the full, generalized theory is applied that interprets also the weak circular polarization Stokes profile. In most cases a unique solution can be found through additional information available from disk field polarity. Title: New observations of the Solar Emission Corona in Fe X and Fe XIV Authors: Smartt, R. N.; Zirker, J. B. Bibcode: 1984stp..conf..269S Altcode: No abstract at ADS Title: Vector Magnetic Fields in Prominences - Part Three - Hei d3 Stokes Profile Analysis for Quiescent and Eruptive Prominences Authors: Athay, R. G.; Querfeld, C. W.; Smartt, R. N.; Landi Degl'Innocenti, E.; Bommier, V. Bibcode: 1983SoPh...89....3A Altcode: Observations of linear polarization in two resolved components of HeI D3 are interpreted using the Hanle effect to determine vector magnetic fields in thirteen prominences. As in all vector magnetic field measurements, there is a two-fold ambiguity in field direction that is symmetric to a 180° rotation about the line-of-sight. The polar angles of the fields show a pronounced preference to be close to 90° from the local solar radius, i.e., the field direction is close to horizontal. Azimuth angles show internal consistency from point to point in a given prominences, but because of the rotational symmetry, the fields may be interpreted, in most cases, as crossing the prominence either in the same sense as the underlying photospheric fields or in the opposite sense. Title: A White-Light / Fex / Hα Coronal Transient Observation to 10-SOLAR-RADII Authors: Wagner, W. J.; Illing, R. M. E.; Sawyer, C. B.; House, L. L.; Sheeley, N. R., Jr.; Howard, R. A.; Koomen, M. J.; Michels, D. J.; Smartt, R. N.; Dryer, M. Bibcode: 1983SoPh...83..153W Altcode: Multi-telescope observations of the coronal transient of 15-16 April, 1980 provide simultaneous data from the Solar Maximum Mission Coronagraph/Polarimeter, the Solwind Coronagraph, and the new Emission Line Coronagraph of the Sacramento Peak Observatory. An eruptive prominence-associated white light transient is for the first time seen as an unusual wave or brightening in Fe Xgl6374 (but not in Fe XIVgl5303). Several interpretations of this fleeting enhancement are offered. Title: Test of vacuum vs helium in a solar telescope. Authors: Engvold, O.; Dunn, R. B.; Livingston, W. C.; Smartt, R. N. Bibcode: 1983ApOpt..22...10E Altcode: The consequences of filling a solar telescope with helium, a gas with an exceptionally low index of refraction and a high thermal conductivity, are reported. All the tests are conducted with the solar beam present to provide normal heating. Internal seeing of the telescope is evaluated by viewing the image of an He-Ne laser beam in autocollimation reflected from the entrance window for different pressures of air or helium. The total path of the laser beam through the tank (six times) becomes about 100 m. Quantitative measurements of the wave front distortions are derived by inserting a point-diffraction interferometer near the focused image of the laser beam. Excursions of the fringe pattern yield direct measures of the wave front errors in units of the 0.633-micron laser wavelength. It is concluded that a helium-filled telescope is a realistic alternative to a vacuum telescope for solar observations. The barely detectable tank seeing with helium near atmospheric pressure could possibly be rectified either by a high reflectivity coating of the mirrors, which reduces the heat load, or by a forced circulation of the helium in the tank. Title: Precision Tuning and Improved Stability of a Universal Birefringent Filter Authors: Stauffer, F. R.; Smith, G. H.; Streander, G. W.; Wilkins, L. M.; November, L. J.; Smartt, R. N. Bibcode: 1983SPIE..380...77S Altcode: Basic modifications of the Sacramento Peak Observatory Universal Birefringent Filter system and resultant major improvements in its performance are described. Spectral tuning is accomplished by rotating the nine birefringent elements that comprise the filter. For this, stepper motors are used under computer control, where one step is equivalent to a precision of 0.0025 Å (at 7000 A) for the narrowest bandpass element. The element angles are accurately set for an arbitrary wavelength by an algorithm derived from known tune solutions. Absolute wavelength calibration is provided by a He-Ne laser source, while an integrated monochromator can be used for the same purpose, though less accurately, throughout the 4100 A to 7000 A spectral range of the filter. The filter is maintained in a thermally stable environment controlled to a precision of 0.05° C; any incremental temperature change in the filter itself can be detected and its effects compensated by means of a laser calibration. In operation, the filter can typically be tuned to a selected wavelength in less than is with a precision of 1 mÅ. Title: Solar corona photoelectric photometer using mica etalons Authors: Smartt, R. N. Bibcode: 1982SPIE..331..442S Altcode: A solar corona photoelectric photometer has been constructed that operates at the three coronal lines, Fe XIV (5302.9 A), Ca XV (5694.5 A) and Fe X (6374.5 A), using mica etalons and narrow-band interference filters. The photometer is used with a 40-cm coronagraph feed. In each case, the corona is discriminated from the sky background, by means of polarization-chopping between the line passband and a reference continuum passband. A mica etalon allows the reference passband to be arbitrarily located in the vicinity of the spectral line. Also, the width of the etalon passbands can be matched to that of the coronal line width, and the transmittance can be high if extremely transparent mica is used. A photomultiplier detects the two signals, their difference being proportional to coronal radiance. The photometer performance is illustrated by radiance plots derived from observations obtained at a fixed height in the corona at equally-incremented field points around the limb. Title: Vector Magnetic Fields in Prominences - Part One - Preliminary Discussion of Polarimeter Observations in he i D3 Authors: House, L. L.; Smartt, R. N. Bibcode: 1982SoPh...80...53H Altcode: A preliminary discussion is presented of measurements of the polarization of the He I D3 multiplet in a quiescent prominence, observed with a wavelength-scanning Stokes polarimeter. For a series of 43 observations in the same prominence, the linear polarization of the major component of D3 lies primarily in the range 1 to 2% and of the wing component, the range 2 to 5%; the polarization vector angle lies primarily in the range 10-25° for the major component, and 25-35° for the other component. From a more limited data set, the polarization of both components is found to first increase as a function of height in the prominence, and then to decrease; the polarization angles of the major component vary in a random-like way with height, while the wing component shows a systematic change. The amount of polarization and the angle of polarization are governed by the Hanle effect. The collective effect of the group of lines at the peak of D3 evidently has a different sensitivity to the Hanle effect than does the wing component, thus yielding at least four independent measurements - two polarizations and two angles. With some redundancy, the vector magnetic field can then be established using the detailed theory of the Hanle effect. Since the wing component of D3 is a simple triplet, an initial estimate of the magnetic field strength and its horizontal orientation, 0, relative to the line of sight, is simply obtained. Examples of such calculations are presented. Title: Coronal Emission Associated with a Quiescent Prominence Authors: Smartt, R. N.; Zhang, Z. Bibcode: 1982BAAS...14Q.623S Altcode: No abstract at ADS Title: Interferometric eclipse observations of the Fe XIV inner corona. Authors: Smartt, R. N.; Zirker, J. B.; Mauter, H. A. Bibcode: 1982PINSA..48..102S Altcode: No abstract at ADS Title: Interferometric Eclipse Observations of the Fe XIV Inner Corona Authors: Smartt, R. N.; Zirker, J. B.; Mauter, H. A. Bibcode: 1982PIAS...48..102S Altcode: No abstract at ADS Title: Interferometric Eclipse Observations of the Fe XIV Inner Corona Authors: Smartt, R. N.; Zirker, J. B.; Mauter, H. A. Bibcode: 1982tsef.conf..102S Altcode: No abstract at ADS Title: Design and performance of a new emission-line coronograph. Authors: Smartt, R. N.; Dunn, R. B.; Fisher, R. R. Bibcode: 1981SPIE..288..395S Altcode: A new emission-line solar coronagraph is described that photographically records coro-nal emission of the Fe XIV (5303 Å) and Fe X (6374 Å) lines, and prominences and the solar disk in Hα (6563 Å). The basic optical system consists of a 20-cm aperture, f/11 aspheric singlet objective and four secondary optical systems--one for each image channel--that are sequentially switched into the beam. Interference filters and a specially-designed Lyot birefringent filter isolate spectral bands ≍ 1 Å at the three wavelengths. The efficiency of this filtering and special constructional features result in an exceptionally small amount of scattered light reaching the film plane. Coronal images can be recorded in skies some 2.5 times brighter than is typical for earlier designs of emission-line corona-graphs. Features of the data obtained so far, including high contrast and high spatial resolution images and the detection of extremely rapid coronal changes, are discussed. Title: Eclipse observations of coronal Fe XIV emission. Authors: Smartt, R. N.; Zirker, J. B.; Mauter, H. A. Bibcode: 1981otse.conf...36S Altcode: No abstract at ADS Title: Quiescent Prominence Vector Magnetic Fields Inferred from He I D3 Polarization Authors: Querfeld, C. W.; Smartt, R. N.; Bommier, V.; Landi Degl'Innocenti, E. Bibcode: 1980BAAS...12..792Q Altcode: No abstract at ADS Title: Vector Magnetic Fields Inferred from He I D3 Polarization in the August 5, 1980 Eruptive Prominence Authors: Querfeld, C. W.; Smartt, R. N.; Bommier, V.; Landi Degl'Innocenti, E. Bibcode: 1980BAAS...12..913Q Altcode: No abstract at ADS Title: Comparison of Coronal Emission-Line Structure and Observed Polarization Authors: Smartt, R. N.; Querfeld, C. W. Bibcode: 1980BAAS...12..793S Altcode: No abstract at ADS Title: A Three-Coronagraph Record from 1 to 10 RO of the Energetics of a Coronal Transient Authors: Wagner, W. J.; Sawyer, C.; Illing, R. M. E.; House, L. L.; Querfeld, C. W.; Sheeley, N. R., Jr.; Howard, R. A.; Koomen, M. J.; Michels, D. J.; Smartt, R. N. Bibcode: 1980BAAS...12Q.902W Altcode: No abstract at ADS Title: Interferometric Eclipse Observations of Coronal Fexiv Emission Authors: Smartt, R. N.; Zirker, J. B.; Mauter, H. A. Bibcode: 1980BASI....8...59S Altcode: No abstract at ADS Title: Solar corona spectra observations in active, quiescent and hole regions. Authors: Gilliam, L. B.; Smartt, R. N.; Zirker, J. B. Bibcode: 1980BAAS...12..751G Altcode: No abstract at ADS Title: Polarization Measurements of Prominences - Characteristics of Stokes Profiles Authors: Smartt, R. N.; House, L. L. Bibcode: 1979BAAS...11..409S Altcode: No abstract at ADS Title: Point-Diffraction Interference Microscopy Authors: Smartt, R. N.; Steel, W. H. Bibcode: 1979JOSA...69.1455S Altcode: 1979OSAJ...69.1455S No abstract at ADS Title: Scattered-light measurements of optical surfaces Authors: Smartt, R. N. Bibcode: 1979SPIE..190...58S Altcode: Measurements of the angular distribution of scattered light produced by specially-polished optical components are reported. The components were six 12-cm aperture coronagraph objective mirrors and two 20-cm coronograph objective lenses. For each test the component was illuminated with white light and the magnitude of the scattered flux measured at several field points. It was not feasible to separate surface and body scattering of the lenses, so that these measurements represent the combined contributions. Successive recoatings and tests of the mirrors has led to the conclusion that the residual roughness of the substrate polish is the dominant parameter that determines the magnitude of the scattered flux. Dark ground and phase contrast measurements qualitatively support this conclusion. The fractional contributions of integrated scattered light of the lenses and mirrors are found to be of the same order, although the functional relationships are significantly different over the angular range measured. Title: Special applications of the point-diffraction interferometer Authors: Smartt, R. N. Bibcode: 1979SPIE..192...35S Altcode: Characteristics and applications of the point-diffraction interferometer (PDI) are discussed, including the effects of moving the aperture in various directions. The test of an astronomical telescope using a stellar source emphasized the benefits to an accurate error analysis of excellent atmospheric seeing conditions. Also considered are a test of a telescope with an He-Ne laser source at a distance of 2.3 km and a test of the universal birefringent filter system. It is concluded that the PDI is an extremely convenient device to test complex optical systems in situ, on- and off-axis, especially in cases where a double-pass configuration is not practicable, where vibration sources are not negligible and where a direct, rapid measure of the wavefront aberration is desirable. Title: Discussion Authors: Landi Degl'Innocenti, M.; Kundu, M. R.; Landman, D. A.; Smartt, R. N.; Stenflo, J. Bibcode: 1979phsp.coll...85L Altcode: 1979IAUCo..44...85D; 1979phsp.coll...85D No abstract at ADS Title: Stokes Polarimetry of Quiescent Prominences in HeI D3. Authors: House, L. L.; Smartt, R. N. Bibcode: 1979phsp.coll...81H Altcode: 1979IAUCo..44...81H; 1979phsp.conf...81H No abstract at ADS Title: Stokes Polarimetry of Quiescent Prominences in He I D3 Authors: House, L. L.; Smartt, R. N. Bibcode: 1978BAAS...10..672H Altcode: No abstract at ADS Title: Zone-Plate Radial-Shear Interferometer Authors: Smartt, R. N. Bibcode: 1978JOSA...68.1391S Altcode: 1978OSAJ...68.1391S No abstract at ADS Title: Scattering Properties of Coronagraph Objective Lenses and Mirrors. Authors: Smartt, R. N. Bibcode: 1977BAAS....9..370S Altcode: No abstract at ADS Title: Absolute measurements of optical flats (A) Authors: Smartt, Raymond N. Bibcode: 1976JOSA...66.1104S Altcode: 1976OSAJ...66.1104S No abstract at ADS Title: Observations of the near-infrared solar corona and a new interferometric telescope test Authors: Smartt, Raymond Newton Bibcode: 1976PhDT.......366S Altcode: No abstract at ADS Title: Observations of the Near-Infrared Solar Corona and a New Interferometric Telescope Test. Authors: Smartt, R. N. Bibcode: 1976PhDT.........3S Altcode: Observations of the infrared outer solar corona were carried out, two with a balloon-borne infrared scanning coronagraph during balloon flights on October, 1973, and the other, ground-based at the June 30, 1973, total solar eclipse. The performance of the 6-detector coronagraph was evaluated, particularly with regard to its novel dual reflective optical systems. The coronagraph balloon flight radiance data, derived from coronal scans spanning elongations of approximately 3-13 solar radii, and a wavelength range of 2-4 microns, is presented. The eclipse data represents the coronal elongation radiance distribution parallel to the ecliptic, over a range of approximately 2-9 solar radii, at a wavelength of 1 micron. A new two-beam interferometer and its application to the testing of telescopes are also described. The interferometer is positioned at the image of a point source, and forms a spherical reference wavefront by diffraction of part of the incident light. Field tests using both star and laser sources were successful. Title: Theory and Application of Point-Diffraction Interferometers Authors: Smartt, R. N.; Steel, W. H. Bibcode: 1975JaJAP..14...14S Altcode: No abstract at ADS Title: Simple unequal-path interferometer configurations (A) Authors: Smartt, Raymond N. Bibcode: 1975JOSA...65.1210S Altcode: 1975OSAJ...65.1210S No abstract at ADS Title: Zone plate interferometer Authors: Smartt, Raymond N. Bibcode: 1974ApOpt..13.1093S Altcode: 1974ApOpt..13..109S Available from http://www.opticsInfoBase.org/abstract.cfm?id=18526; Title: Point-Diffraction Interferometer Authors: Smartt, R. N.; Strong, J. Bibcode: 1974OptEn..13.G198S Altcode: No abstract at ADS Title: Point-Diffraction Interferometer Authors: Smartt, R. N.; Strong, J. Bibcode: 1974JOSA...62..737S Altcode: 1974OSAJ...62..737S No abstract at ADS Title: Telescope Test using the Point-Diffraction Interferometer Authors: Smartt, R. N. Bibcode: 1974JOSA...64..558S Altcode: 1974OSAJ...64..558S No abstract at ADS Title: Coronagraph Mirrors for the Near Infrared Authors: Smartt, R. N.; Dalton, W. S. Bibcode: 1971JOSA...61..665S Altcode: 1971OSAJ...61..665S No abstract at ADS Title: A Variable Transmittance Beam Splitter Authors: Smartt, R. N. Bibcode: 1970ApOpt...9..970S Altcode: No abstract at ADS Title: Fresnel Zone Plate Interferometer Authors: Smartt, R. N.; Givens, M. P. Bibcode: 1969JOSA...59.1522S Altcode: 1969OSAJ...59.1522S No abstract at ADS Title: Mica Polarizing Prism Authors: Dumont, F. J.; Smartt, R. N. Bibcode: 1969JOSA...59.1541D Altcode: 1969OSAJ...59.1541D No abstract at ADS Title: A Tunable Birefringent Fabry-Perot Interferometer Authors: Ramsay, J. V.; Smartt, R. N. Bibcode: 1966ApOpt...5.1341R Altcode: No abstract at ADS Title: On the Production and Use of the Optical-Contact Bond Authors: Smartt, R. N.; Ramsay, J. V. Bibcode: 1964JPhE...41..514S Altcode: No abstract at ADS Title: A 1/8 A Birefringent Filter for Solar Research Authors: Steel, W. H.; Smartt, R. N.; Giovanelli, R. G. Bibcode: 1961AuJPh..14..201S Altcode: No abstract at ADS Title: The Production of High-Quality Optical Surfaces on Calcite Authors: Smartt, R. N. Bibcode: 1961JPhE...38..165S Altcode: No abstract at ADS Title: Birefringence of quartz and calcite Authors: Smartt, R. N.; Steel, W. H. Bibcode: 1959JOSA...49..710S Altcode: 1959OSAJ...49..710S No abstract at ADS