Author name code: frazier ADS astronomy entries on 2022-09-14 author:"Frazier, Edward N." ------------------------------------------------------------------------ Title: EOS Chemistry spacecraft Authors: Frazier, Edward N.; Rasmussen, Amy L. Bibcode: 1998SPIE.3498...53F Altcode: The EOS Chemistry mission is the third of the 'flagship' missions of NASA's Earth Sciences Enterprise, following EOS AM and EOS PM. Design work on the Chemistry spacecraft has started under NASA contract NAS5-32954. This spacecraft is the second of the EOS Common Spacecraft, EOS PM being the first one. The design has recently been successfully completed with spacecraft CDR this June, and it is now in the fabrication phase for the PM mission. This design of the spacecraft will be summarized. The Chemistry mission will carry four new scientific instruments. These instruments place some new requirements on the spacecraft to accommodate them, but these are satisfied with relatively small 'kits' that are added to the Common Spacecraft design. This design of the Chemistry configuration of the Common Spacecraft will be presented. We have explored the cost effectiveness of small and medium satellite architectures for hypothetical future Earth Science missions. These cost comparisons include the life cycle cost of space, launch and ground segments of each complete mission and are based on actual costs of existing missions. We find that the lowest cost approach under a wide variety of assumptions is to use a medium size spacecraft carrying a suite of instruments. Title: A self-consistent model of the zodiacal light radiance. Authors: Frazier, Edward N.; Boucher, Donald J.; Mueller, Gary F. Bibcode: 1987SPIE..819....2F Altcode: A model of zodiacal light IR radiation is generalized to encompass the effects of scattered sunlight. The model is compared with existing data on scattered visible light in order to test compatibility between IR and visible data, so that both can be explained by a single, self-consistent model of the interplanetary dust. Both the IR emission and the visible scattering calculations are based on the Mie equation, with the optical constants of the interplanetary dust being the input parameters. The space and size distributions of the dust particles are explicitly parameterized. The results show that the IR and visible data are compatible, and can be matched by adjusting the continuous opacity within reasonable bounds. Title: Infrared Radiation of the Zodiacal Light Authors: Frazier, E. N. Bibcode: 1985SPIE..513..216F Altcode: No abstract at ADS Title: Simulation of the Magnetic Structure of the Inner Heliosphere by Means of a Non-Spherical Source Surface Authors: Levine, R. H.; Schulz, M.; Frazier, E. N. Bibcode: 1982SoPh...77..363L Altcode: In this work we implement a new method for mapping the Sun's magnetic field B from the photosphere through the corona and interplanetary space. The method entails the derivation of B from a scalar potential within a `current-free' annular volume bounded inside by the photosphere and outside by a prescribed non-spherical `source surface' to which B is made (as nearly as possible) perpendicular. As usual we obtain the potential for the part of B that arises from currents inside the Sun by fitting an expansion to the observed line-of-sight component of B at the photosphere. The new aspect of our work is that we introduce a second least-squares fit to obtain the part of B that arises from currents outside the source surface. We do this by minimizing the mean-square tangential component of B over the source surface. This latter prescription allows a nearly arbitrary specification of the source surface, and no particular symmetry properties need be invoked for it. We have chosen as our prescription of the source surface one that reasonably simulates the expected physical consequences of coronal MHD effects. The magnetic field exterior to the source surface is made perpendicular to the source surface and is mapped throughout the heliosphere by means of a geometrical construction that appropriately generalizes the Parker spiral. Detailed comparisons have been made between this new model and observed coronal and interplanetary structures. The equatorward inclination of coronal helmet streamers is modeled much better with a non-spherical source surface than with a spherical one. There is clear evidence, however, that observational data underestimate the strength of photospheric polar magnetic fields. Neutral lines on the source surface (i.e., contours on which the normal component of B vanishes) generate heliospheric current sheets outside the source surface. In the particular case studied, two separate current sheets existed and were carried by the solar wind from the source surface to the boundary of the heliosphere. The result was a four-sector magnetic configuration near the ecliptic at 1 AU, and the observations were in good agreement with this prediction of the model. Title: Simulation of the magnetic structure of the inner heliosphere by means of non-spherical source surface Authors: Levine, R. H.; Schulz, M.; Frazier, E. N. Bibcode: 1981STIN...8118977L Altcode: A new method for mapping the Sun's magnetic field B from the photosphere through the corona and interplanetary space is presented. The method entails the derivation of B from a scalar potential within a current-free annular volume bounded inside by photosphere and outside by a prescribed nonspherical source surface to which B is made (as nearly as possible) perpendicular. As usual we obtain the potential for the part of B that arises from currents inside the Sun by fitting an expansion to the observed line-of-sight component of B at the photosphere. A second least-squares fit is introduced to obtain the part of B that arises from currents outside the source surface. Comparisons are made between this model and observed coronal and interplanetary structures. There is evidence that observation data underestimate the strength of photospheric polar magnetic fields. Title: The Non-Spherical Source Surface Magnetic Model: Comparison with Coronal Data Authors: Frazier, E. N.; Schulz, M.; Levine, R. H. Bibcode: 1980BAAS...12..544F Altcode: No abstract at ADS Title: The Measurement of Global Scale Surface Dynamics Authors: Frazier, E. N. Bibcode: 1980NASCP2098..147F Altcode: 1980sscs.nasa..147F The SCADM mission implicitly contains a requirement for a fundamentally new type of satellite instrument: a very sensitive (approximately 1 m s/1) imaging velocity detector. This is needed to measure global oscillations and global circulation patterns, but the sensitivity requirement is so severe that it has not yet been met even with ground based instruments. In this presentation, the various possible sources of noise and other errors in such a device are considered, and the more detailed instrumental requirements are developed. This leads to the conceptual design of a velocity graph that appears to achieve the necessary sensitivity and imaging capability within a resonable weight and volume. Title: Improved Models of Coronal Magnetic Structure: The Non-Spherical Source Surface Authors: Levine, R. H.; Schulz, M.; Frazier, E. N. Bibcode: 1979BAAS...11..697L Altcode: No abstract at ADS Title: Magnetic, velocity and brightness structure of solar faculae. Authors: Frazier, E. N.; Stenflo, J. O. Bibcode: 1978A&A....70..789F Altcode: To investigate the magnetic, velocity, and brightness structure of solar magnetic elements in active region plages, the line-ratio technique of Stenflo (1973) was applied by making simultaneous magnetograph recordings in the two Fe I lines at 525.0 and 524.7 nm. Not only the B(525.0)/B(524.7) ratio but also the brightness-magnetic field and velocity-magnetic field correlations were studied. The center-to-limb variations of the parameters were also observed. The data were analyzed in terms of a Milne-Eddington model atmosphere. The cross section of the magnetic field was found to be narrower than the associated velocity profile. The continuum contrast at disk center had an amplitude of as much as 18%, which indicates that the heating starts at relatively large optical depths, with temperature excess increasing rapidly with height to account for the strong intensity enhancement in the line core. With the M-E model, however, it was not possible to obtain a fully consistent fit with all data at the same time. One needs a multidimensional, time-dependent non-LTE model for the transfer of polarized light in rapidly evolving small-scale magnetic geometries Title: Coronal magnetic-field model with non-spherical source surface. Authors: Schulz, M.; Frazier, E. N.; Boucher, D. J., Jr. Bibcode: 1978SoPh...60...83S Altcode: Previous global models of coronal magnetic fields have used a geometrical construction based on a spherical source surface because of requirements for computational speed. As a result they have had difficulty accounting for (a) the tendency of full magnetohydrodynamic (MHD) models to predict non-radial plasma flow out to r ∼ 10r and (b) the appreciable magnitude, ∼ 3γ, of Br, (the radial component of B) consistently observed at r ∼ 1 AU. We present a new modelling technique based on a non-spherical source surface, which is taken to be an isogauss of the underlying potential field generated by currents in or below the photosphere. This modification of the source surface significantly improves the agreement between the geometrical construction and the MHD solution while retaining most of the computational ease provided by a spherical source surface. A detailed comparison between the present source-surface model and the MHD solution is made for the internal dipole case. The resulting B field agrees well in magnitude and direction with the coronal B field derived from the full MHD equations. It shows evidence of the slightly equatorward meridional plasma flow that is characteristic of the MHD solution. Moreover, the B field obtained by using our non-spherical source surface agrees well with that observed by spacecraft in the vicinity of the Earth's orbit. Applied to a solar dipole field with a moment of 1 G-r3, the present model predicts that Br at r ∼ 1 AU lies in the range of ∼ 1-2γ and is remarkably insensitive to heliomagnetic latitude. Our method should be applicable also to more general (i.e., more realistic) configurations of the solar magnetic field. Isogauss surfaces for two representative solar rotations, as calculated from expansions of observed photospheric magnetic-field data, are found to show large and significant deviations from sphericity. Title: Coronal magnetic-field model with nonspherical source surface Authors: Schulz, M.; Frazier, E. N.; Boucher, D. J., Jr. Bibcode: 1978aero.reptQ....S Altcode: Previous global models of coronal magnetic fields have used a geometrical construction based on a spherical source surface because of requirements for computational speed. As a result they have had difficulty accounting for the tendency of full magnetohydrodynamic (MHD) models to predict non-radial plasma flow out to r about 10 solar radii and the appreciable magnitude, about 3 gamma, of Br (the radial component of B) consistently observed at r about 1 AU. A new modelling technique based on a nonspherical source surface is presented, which is taken to be an isogauss of the underlying potential field generated by currents in or below the photosphere. This modification of the source surface significantly improves the agreement between the geometrical construction and the MHD solution while retaining most of the computational ease provided by a spherical source surface. Title: Line profile families of faculae and pores. Authors: Frazier, E. N. Bibcode: 1978A&A....64..351F Altcode: It is pointed out that for any given Fraunhofer line, there should exist an entire range of facular line profiles. The consequences of the hypothesis that the structure of faculae and pores is determined to first order by the total magnetic flux is examined, and therefore, there should be a one parameter family of line profiles, with the magnetic flux being that parameter. Observations from a magnetograph are used to construct this family of line profiles in a statistical manner. Results are given for the two absorption lines, Fe I 525.022 nm and Fe I 524.706 nm. It is shown that the shape of these profiles changes continuously from the smallest to the largest faculae, even including pores. It is concluded that the T(tau) relation in faculae and pores is a strong function of the total flux, and that a generalized model of this phenomenon is needed. An additional effect of this phenomenon is that past observations of facular line profiles and continuum contrasts have probably been seriously contaminated by observational selection. Title: Infrared radiation of the zodiacal light. Authors: Frazier, E. N. Bibcode: 1977muit.conf..139F Altcode: No abstract at ADS Title: Line profiles of faculae and pores. Authors: Frazier, E. N. Bibcode: 1977IAUS...62..255F Altcode: No abstract at ADS Title: The Photosphere - Magnetic and Dynamic State Authors: Frazier, E. N. Bibcode: 1976RSPTA.281..295F Altcode: 1976RSLPT.281..295F The photosphere is essentially a relatively thin boundary layer between two fundamentally different plasma regimes. The solar interior is characterized by high density, high opacity, high β and convective instability, whereas the outer solar atmosphere has the opposite properties. The convection in the interior provides the ultimate driving force for all of the dynamic and magnetic structure of the solar atmosphere, yet when we view the photosphere, we can observe only the upper boundary of the convection zone. Instead, we observe primarily its various after-effects: overshoot, wave propagation, and confinement of the magnetic field. These observable phenomena are described with a view toward diagnosing the essential physics above and below the photosphere. The convective modes, granulation and supergranulation, are reviewed briefly; the oscillatory modes are discussed in somewhat more detail. Finally, the magnetic structure of the photosphere is described. Title: A realistic approach to magnetic evolution. Authors: Frazier, E. N. Bibcode: 1976SoPh...47..205F Altcode: An improved scheme for measuring and analyzing the magnetic field of flares is presented in general outline form. The techniques employed during the last solar cycle are reviewed very briefly. The point is made that those techniques were inadequate due to fundamental limitations in the data. A realistic scheme for acquiring the necessary data is then proposed. The scheme is realistic in that it makes only those assumptions which appear to be indeed valid, and it presupposes only instrumental techniques which are presently available. It is suggested that, with this improved data, the structure and evolution of the pre-flare magnetic field can be calculated with sufficient accuracy to form the basis of theoretical models. Title: On the statistical desription of inhomogeneities in the quiet solar atmosphere. I. Linear regression analysis and absolute calibration of multichannel observations of the Ca+ emission network. Authors: Skumanich, A.; Smythe, C.; Frazier, E. N. Bibcode: 1975ApJ...200..747S Altcode: Observations with a 2';4 square aperture (1968 epoch) of the Ca + K core brightness (1.1 A bandwidth), vertical magnetic field, vertical velocity, and continuum brightness have been analyzed to yield average network and nonnetwork values and dispersions as well as linear regression relations. The statistics of all variables but the continuum consist of a symmetric core superposed on an extended tail which is associated with the chromospheric network. Network statistics were derived by subtraction of a Gaussian fit to the core which was taken to represent nonnetwork fluctuations. The velocity network was only partially resolved so that its distribution, and that of the continuum, was obtained by identifying network regions as those with field > 10 gauss. The average network has a field of 26 gauss, independent of polarity, a Ca + brightness 1.27 that of the average nonnetwork or undisturbed chromosphere, a downdraft velocity of 41 m a monochromatic continuum enhancement of 0.34 percent, and covers 39 percent of the quiet Sun. The network brightness increases relative to its average with a slope of 2.1 percent gauss-1 for Ca + and 2.6 percent gauss -1 for the continuum while the downdraft velocity increases by 1.6 m 1 gauss-1 for fields between 25 and 120 gauss. Nonlinear effects appear for larger and smaller fields. The average outward flux density of network over nonnetwork regions is 2.4 >c 10 ergs 1 forCa+ Kand 3.8 x l08ergscm-2s-1 for the continuum. Photometric calibration of the Ca + K line observations was effected by a comparison of the observed relative contrast statistics with a statistically equivalent absolute brightness distribution obtained from a calibrated slit spectrum of the Ca + K line. Subject headings:atmospheres, solar - Ca ii emission - magnetic fields, solar - solar atmospheric motions Title: How to Observe Faculae Authors: Frazier, E. N. Bibcode: 1975BAAS....7..472F Altcode: No abstract at ADS Title: A Velocity Error in Babcock-Type Magnetographs Authors: Frazier, E. N. Bibcode: 1974SoPh...38...69F Altcode: An associated error exists in the velocities observed with Babcock-type magnetographs. This error is used to derive information concerning the fine structure of magnetic field regions. To calculate a velocity error which agrees with observation a generalization of Stenflo's model of a profile of a magnetic filament is used. The model calculation is compared with the observational data to show that the reproduction of the observed velocity error with reasonable values of the free parameter in the three Stenflo filament profiles is possible. Title: The Small-Scale Structure of Solar Velocity Fields Authors: Frazier, E. N. Bibcode: 1974BAAS....6..287F Altcode: No abstract at ADS Title: Motions of Chromospheric Fine Structures Authors: Frazier, E. N. Bibcode: 1974IAUS...56...97F Altcode: No abstract at ADS Title: A New Dual Filter Telescope Authors: Frazier, E. N. Bibcode: 1973BAAS....5U.272F Altcode: No abstract at ADS Title: On the Small-Scale Structure of Solar Magnetic Fields Authors: Frazier, E. N.; Stenflo, J. O. Bibcode: 1972SoPh...27..330F Altcode: The small-scale structure of solar magnetic fields has been studied using simultaneous recordings in the spectral lines Fe I 5250 Å and Fe I 5233 Å, obtained with the Kitt Peak multi-channel magnetograph. We find that more than 90% of the magnetic flux in active regions (excluding the sunspots), observed with a 2.4 by 2.4″ aperture, is channelled through narrow filaments. This percentage is even higher in quiet areas. The field lines in a magnetic filament diverge rapidly with height, and part of the flux returns back to the neighbouring photosphere. Therefore the strong fields within a magnetic filament are surrounded by weak fields of the order of a few gauss of the opposite polarity. The field-strength distribution within a filament, including the surrounding opposite-polarity fields, seems to be almost the same for all filaments within a given active or quiet region. Title: Comments on the Paper 'Fine Structure of Solar Magnetic Fields' by H. Zirin Authors: Frazier, Edward N. Bibcode: 1972SoPh...26..142F Altcode: No abstract at ADS Title: The Magnetic Structure of Arch Filament Systems Authors: Frazier, Edward N. Bibcode: 1972SoPh...26..130F Altcode: Photographic-type magnetograms are used in conjunction with Hα filtergrams to study the structure and evolution of magnetic fields associated with arch filament systems. The magnetograms show that the opposite ends of the arch filaments are indeed rooted in photospheric magnetic fields of opposite polarity. Furthermore, these magnetic field systems are in every case new magnetic flux appearing at the solar surface. Time lapse studies show the detailed process by which the flux tubes emerge through the surface. First, supergranules bring individual strands of magnetic flux to the surface and sweep the two feet of the flux tube to opposite sides of the supergranule. Then, the flux tube rises through the chromosphere, creating a visible arch filament. It is also shown that the observed rotation of the axis of an arch filament system in the plane of the solar surface is caused by the emergence of successive flux loops, each possessing different axial tilts. Title: On the Quantitative Description of the Fluctuating Solar Atmosphere. I. Regression Analysis and Calibration of Multi-channel Observations Authors: Skumanich, A.; Smythe, C.; Frazier, E. N. Bibcode: 1972BAAS....4W.391S Altcode: No abstract at ADS Title: The Relations between Chromospheric Features and Photospheric Magnetic Fields Authors: Frazier, Edward N. Bibcode: 1972SoPh...24...98F Altcode: High resolution photographic magnetograms are compared with Hα filtergrams (both on- and off - band) for a wide variety of solar features. It is verified that Hα filaments overlie neutral lines or bands and that Hα plages always occur at magnetic field clumps. However, the brightness of Hα plages bear no relation to magnetic field strength or polarity, and the direction of the magnetic field with respect to threads and filaments remains obscure. Counter-examples can be found for virtually every `rule' that has been formulated so far. Title: On the Filamentary Nature of Active-Region Magnetic Fields Authors: Stenflo, J. O.; Frazier, E. N. Bibcode: 1972lfpm.conf..295S Altcode: No abstract at ADS Title: Multi-Channel Magnetograph Observations. III: Faculae Authors: Frazier, Edward N. Bibcode: 1971SoPh...21...42F Altcode: Simultaneous observations of photospheric magnetic fields, CaII K emission, the `photospheric network' and continuum faculae show that these four quantities are correlated in a complicated manner. The photospheric and calcium networks show increasing contrast with increasing magnetic field strength up to field strengths of about 500 G. Higher values of the magnetic field are found only in pores and sunspots. Continuum faculae also show increasing contrast with increasing magnetic field strength (even at the disk center), but this contrast reaches a maximum at field strengths of about 200 G. At higher field strengths, continuum faculae become monotonically darker until pore or spunspot conditions are reached. Title: Supergranulation at the Center of the Disk Authors: Frazier, E. N. Bibcode: 1971IAUS...43..260F Altcode: No abstract at ADS Title: Multi-Channel Magnetograph Observations. II. Supergranulation Authors: Frazier, Edward N. Bibcode: 1970SoPh...14...89F Altcode: The Kitt Peak multi-channel magnetograph was used to make raster scans of the super-granulation. The region scanned was carefully selected to be quiet and was located at the center of the disk. Each point in the raster was observed twice (with a time interval of 150 sec) and averaged, thereby cancelling out effects of the 5 min oscillations. Subsequent raster scans were made over a period of 4 h and averaged, further reducing short-lived, nonperiodic modes and enhancing the long-lived super-granulation. Title: Supergranulation at the Center of the Solar Disk Authors: Frazier, Edward N. Bibcode: 1970BAAS....2T.192F Altcode: No abstract at ADS Title: Multi-Channel Magnetograph Observations. I: Comparison with Spectroheliograms Authors: Frazier, Edward N.; Scherrer, Philip H. Bibcode: 1969SoPh...10..297F Altcode: A new technique for displaying magnetograph observations is presented and applied to the 12-channel magnetograph at Kitt Peak National Observatory. Using the data from a raster scan, a digital `spectroheliogram' is constructed on the face of a cathode ray tube and photographed. This enables one to recognize patterns in magnetograph data as easily as with conventional photographs. Comparisons with simultaneous spectroheliograms show no qualitative differences and indicate that the magnetograph is quite capable of studying morphology of individual solar features. Title: Computer Display of Magnetograph Observations Authors: Frazier, Edward N. Bibcode: 1969BAAS....1..276F Altcode: No abstract at ADS Title: An Observational Study of the Hydrodynamics of the Lower Solar Photosphere Authors: Frazier, Edward N. Bibcode: 1968ApJ...152..557F Altcode: Velocity and temperature fluctuations in the solar photosphere were studied using a series of high- resolution spectrograms of the same area on the surface of the Sun at intervals of 20 sec for 55 mm The observations were made with the McMath solar telescope at Kitt Peak National Observatory. Doppler shifts and intensity fluctuations were measured on every frame for three lines, Si ii X6371 .36, Fe X6364.38, and Fe X6355.04, and their temporal properties were studied using Fourier analysis techniques. The use of these three lines allowed the author to study the Fourier properties as a function of altitude in the range from the convection zone to the temperature minimum. The power spectrum of the velocity fluctuations showed a large amount of the low-frequency, or convective, component. This low-frequency power was about 70 per cent coherent with the granulation, and in phase with it. Furthermore, it was present at all levels of the photosphere, implying a consider- able amount of convective overshoot all the way up to the temperature minimum. Specifically, 61 per cent of the power at the level of the Si ii line was convective, and 3.5 per cent of this power penetrated to the temperature minimum. The increased Fourier resolution, afforded by the relatively long observing time of 55 mill, resolved the oscillatory (300-sec period) component into two components; a very sharp component with a period of 265 sec, and a weaker, broader component with a period of 345 sec. Both of these periods remain con- stant with altitude. The relative amplitudes of the two components vary with altitude in the sense that the 265-sec component becomes relatively stronger with height. No vertical phase lags were observed at any frequency; the oscillations must be standing waves. The velocity auto-correlation functions showed that these oscillations are extremely long-lived, probably steady state. The power spectra of the intensity fluctuations showed primarily the convective component, again at all levels. Small amounts of oscillatory power were seen, however, in all intensity power spectra. Even the continuum intensity power spectrum contained 10 per cent oscillatory power. The many pairs of coherence and phase spectra yielded additional details of the hydrodynamics of the various modes Title: A Spatio-Temporal Analysis of Velocity Fields in the Solar Photosphere Authors: Frazier, E. N. Bibcode: 1968ZA.....68..345F Altcode: No abstract at ADS Title: A Spatio-Temporal Analysis of Fine-Scale Velocity Fields in the Photosphere. Authors: Frazier, Edward Bibcode: 1968AJS....73Q..61F Altcode: A series of high (spatial) resolution spectrograms were taken of the center of the solar disk at Kitt Peak National Observatory. The spectrograms were taken every 20 seconds for 55 minutes. The Doppler shifts of the absorption lines, as well as the intensity fluctuations, both in the continuum and in the lines, were subjected to a simultaneous spatial and temporal analysis. The results are displayed in the form of contour lines in the k -~ plane, or diagnostic diagram. These results clearly show convective overshoot at all levels of the photosphere. They also show that the well-known 5-minute oscillations are primarily standing resonant acoustic waves. Title: An Observational Study of the Hydrodynamics of the Lower Solar Photosphere Authors: Frazier, E. N. Bibcode: 1966PASP...78..424F Altcode: No abstract at ADS Title: An Observational Study of the Hydrodynamics of the Lower Solar Photosphere . Authors: Frazier, Edward Nelson Bibcode: 1966PhDT.........2F Altcode: No abstract at ADS