Author name code: bethge ADS astronomy entries on 2022-09-14 author:"Bethge, Christian" ------------------------------------------------------------------------ Title: Quiet Sun Center to Limb Variation of the Linear Polarization Observed by CLASP2 Across the Mg II h and k Lines Authors: Rachmeler, L. A.; Bueno, J. Trujillo; McKenzie, D. E.; Ishikawa, R.; Auchère, F.; Kobayashi, K.; Kano, R.; Okamoto, T. J.; Bethge, C. W.; Song, D.; Ballester, E. Alsina; Belluzzi, L.; Pino Alemán, T. del; Ramos, A. Asensio; Yoshida, M.; Shimizu, T.; Winebarger, A.; Kobelski, A. R.; Vigil, G. D.; Pontieu, B. De; Narukage, N.; Kubo, M.; Sakao, T.; Hara, H.; Suematsu, Y.; Štěpán, J.; Carlsson, M.; Leenaarts, J. Bibcode: 2022ApJ...936...67R Altcode: 2022arXiv220701788R The CLASP2 (Chromospheric LAyer Spectro-Polarimeter 2) sounding rocket mission was launched on 2019 April 11. CLASP2 measured the four Stokes parameters of the Mg II h and k spectral region around 2800 Å along a 200″ slit at three locations on the solar disk, achieving the first spatially and spectrally resolved observations of the solar polarization in this near-ultraviolet region. The focus of the work presented here is the center-to-limb variation of the linear polarization across these resonance lines, which is produced by the scattering of anisotropic radiation in the solar atmosphere. The linear polarization signals of the Mg II h and k lines are sensitive to the magnetic field from the low to the upper chromosphere through the Hanle and magneto-optical effects. We compare the observations to theoretical predictions from radiative transfer calculations in unmagnetized semiempirical models, arguing that magnetic fields and horizontal inhomogeneities are needed to explain the observed polarization signals and spatial variations. This comparison is an important step in both validating and refining our understanding of the physical origin of these polarization signatures, and also in paving the way toward future space telescopes for probing the magnetic fields of the solar upper atmosphere via ultraviolet spectropolarimetry. Title: Magnetoseismology for the solar corona: from 10 Gauss to coronal magnetograms Authors: Yang, Zihao; Gibson, Sarah; He, Jiansen; Del Zanna, Giulio; Tomczyk, Steven; Morton, Richard; McIntosh, Scott; Wang, Linghua; Karak, Bidya Binay; Samanta, Tanmoy; Tian, Hui; Chen, Yajie; Bethge, Christian; Bai, Xianyong Bibcode: 2022cosp...44.2490Y Altcode: Magnetoseismology, a technique of magnetic field diagnostics based on observations of magnetohydrodynamic (MHD) waves, has been widely used to estimate the field strengths of oscillating structures in the solar corona. However, previously magnetoseismology was mostly applied to occasionally occurring oscillation events, providing an estimate of only the average field strength or one-dimensional distribution of field strength along an oscillating structure. This restriction could be eliminated if we apply magnetoseismology to the pervasive propagating transverse MHD waves discovered with the Coronal Multi-channel Polarimeter (CoMP). Using several CoMP observations of the Fe XIII 1074.7 nm and 1079.8 nm spectral lines, we obtained maps of the plasma density and wave phase speed in the corona, which allow us to map both the strength and direction of the coronal magnetic field in the plane of sky. We also examined distributions of the electron density and magnetic field strength, and compared their variations with height in the quiet Sun and active regions. Such measurements could provide critical information to advance our understanding of the Sun's magnetism and the magnetic coupling of the whole solar atmosphere. Title: Magnetoseismology for the solar corona: from 10 Gauss to coronal magnetograms Authors: Yang, Zihao; Bethge, Christian; Tian, Hui; Tomczyk, Steven; Morton, Richard; Del Zanna, Giulio; McIntosh, Scott; Karak, Bidya Binay; Gibson, Sarah; Samanta, Tanmoy; He, Jiansen; Chen, Yajie; Bai, Xianyong; Wang, Linghua Bibcode: 2021AGUFMSH12C..07Y Altcode: Magnetoseismology, a technique of magnetic field diagnostics based on observations of magnetohydrodynamic (MHD) waves, has been widely used to estimate the field strengths of oscillating structures in the solar corona. However, previously magnetoseismology was mostly applied to occasionally occurring oscillation events, providing an estimate of only the average field strength or one-dimensional distribution of field strength along an oscillating structure. This restriction could be eliminated if we apply magnetoseismology to the pervasive propagating transverse MHD waves discovered with the Coronal Multi-channel Polarimeter (CoMP). Using several CoMP observations of the Fe XIII 1074.7 nm and 1079.8 nm spectral lines, we obtained maps of the plasma density and wave phase speed in the corona, which allow us to map both the strength and direction of the coronal magnetic field in the plane of sky. We also examined distributions of the electron density and magnetic field strength, and compared their variations with height in the quiet Sun and active regions. Such measurements could provide critical information to advance our understanding of the Sun's magnetism and the magnetic coupling of the whole solar atmosphere. Title: Demonstration of Chromospheric Magnetic Mapping with CLASP2.1 Authors: McKenzie, David; Ishikawa, Ryohko; Trujillo Bueno, Javier; Auchere, F.; Kobayashi, Ken; Winebarger, Amy; Kano, Ryouhei; Song, Donguk; Okamoto, Joten; Rachmeler, Laurel; De Pontieu, Bart; Vigil, Genevieve; Belluzzi, Luca; Alsina Ballester, Ernest; del Pino Aleman, Tanausu; Bethge, Christian; Sakao, Taro; Stepan, Jiri Bibcode: 2021AGUFMSH52A..06M Altcode: Probing the magnetic nature of the Suns atmosphere requires measurement of the Stokes I, Q, U and V profiles of relevant spectral lines (of which Q, U and V encode the magnetic field information). Many of the magnetically sensitive lines formed in the chromosphere and transition region are in the ultraviolet spectrum, necessitating observations above the absorbing terrestrial atmosphere. The Chromospheric Layer Spectro-Polarimeter (CLASP2) sounding rocket was flown successfully in April 2019, as a follow-on to the successful flight in September 2015 of the Chromospheric Lyman-Alpha Spectro-Polarimeter (CLASP). Both projects were funded by NASAs Heliophysics Technology and Instrument Development for Science (H-TIDeS) program to develop and test a technique for observing the Sun in ultraviolet light, and for quantifying the polarization of that light. By demonstrating successful measurement and interpretation of the polarization in hydrogen Lyman-alpha and the Mg II h and k spectral lines, the CLASP and CLASP2 missions are vital first steps towards routine quantitative characterization of the local thermal and magnetic conditions in the solar chromosphere. In October of 2021, we re-flew the CLASP2 payload with a modified observing program to further demonstrate the maturity of the UV spectropolarimetry techniques, and readiness for development into a satellite observatory. During the reflight, called CLASP2.1, the spectrograph slit was scanned across an active region plage to acquire a two-dimensional map of Stokes V/I, to demonstrate the ability of UV spectropolarimetry to yield chromospheric magnetic fields over a large area. This presentation will display preliminary results from the flight of CLASP2.1. Title: Enhancements to Hinode/SOT-SP Vector Magnetic Field Data Products Authors: DeRosa, M. L.; Leka, K. D.; Barnes, G.; Wagner, E.; Centeno, R.; De Wijn, A.; Bethge, C. Bibcode: 2021AAS...23821305D Altcode: The Solar Optical Telescope Spectro-Polarimeter (SOT-SP), on board the Hinode spacecraft (launched in 2006), is a scanning-slit spectrograph that continues to provide polarization spectra useful for inferring the vector (three-component) magnetic field at the solar photosphere. SOT-SP achieves this goal by obtaining line profiles of two magnetically sensitive lines, namely the Fe I 6302 Angstrom doublet, using a 0.16"×164" slit as it scans a region of interest. Once the data are merged, a Milne-Eddington based spectropolarimetric inversion scheme is used to infer multiple physical parameters in the solar photosphere, including the vector magnetic field, from the calibrated polarization spectra. All of these data are publicly available once the processing has occurred.
As of this year, the Hinode/SOT team is also making available the disambiguated vector magnetic field and the re-projected heliographic components of the field. In making the disambiguated vector field data product, the 180° ambiguity in the plane-of-sky component of the vector magnetic field inherent in the spectropolarimetric inversion process has been resolved. This ambiguity is resolved using the Minimum-Energy algorithm, which is the same algorithm used within the pipeline producing the vector-magnetogram data product for the Helioseismic and Magnetic Imager aboard the Solar Dynamics Observatory. The heliographic field components (Bphi, Btheta, Br) on the same grid as the inverted data are also now provided. This poster provides more details about these data product enhancements, and some examples on how the scientific community may readily obtain these data. Title: Mapping of Solar Magnetic Fields from the Photosphere to the Top of the Chromosphere with CLASP2 Authors: McKenzie, D.; Ishikawa, R.; Trujillo Bueno, J.; Auchere, F.; del Pino Aleman, T.; Okamoto, T.; Kano, R.; Song, D.; Yoshida, M.; Rachmeler, L.; Kobayashi, K.; Narukage, N.; Kubo, M.; Ishikawa, S.; Hara, H.; Suematsu, Y.; Sakao, T.; Bethge, C.; De Pontieu, B.; Vigil, G.; Winebarger, A.; Alsina Ballester, E.; Belluzzi, L.; Stepan, J.; Asensio Ramos, A.; Carlsson, M.; Leenaarts, J. Bibcode: 2021AAS...23810603M Altcode: Coronal heating, chromospheric heating, and the heating & acceleration of the solar wind, are well-known problems in solar physics. Additionally, knowledge of the magnetic energy that powers solar flares and coronal mass ejections, important drivers of space weather, is handicapped by imperfect determination of the magnetic field in the sun's atmosphere. Extrapolation of photospheric magnetic measurements into the corona is fraught with difficulties and uncertainties, partly due to the vastly different plasma beta between the photosphere and the corona. Better results in understanding the coronal magnetic field should be derived from measurements of the magnetic field in the chromosphere. To that end, we are pursuing quantitative determination of the magnetic field in the chromosphere, where plasma beta transitions from greater than unity to less than unity, via ultraviolet spectropolarimetry. The CLASP2 mission, flown on a sounding rocket in April 2019, succeeded in measuring all four Stokes polarization parameters in UV spectral lines formed by singly ionized Magnesium and neutral Manganese. Because these ions produce spectral lines under different conditions, CLASP2 thus was able to quantify the magnetic field properties at multiple heights in the chromosphere simultaneously, as shown in the recent paper by Ishikawa et al. In this presentation we will report the findings of CLASP2, demonstrating the variation of magnetic fields along a track on the solar surface and as a function of height in the chromosphere; and we will illustrate what is next for the CLASP missions and the demonstration of UV spectropolarimetry in the solar chromosphere. Title: Mapping the global magnetic field in the solar corona through magnetoseismology Authors: Yang, Zihao; Bethge, Christian; Tian, Hui; Tomczyk, Steven; Morton, Richard; Del Zanna, Giulio; McIntosh, Scott; Karak, Bidya Binay; Gibson, Sarah; Samanta, Tanmoy; He, Jiansen; Chen, Yajie; Wang, Linghua; Bai, Xianyong Bibcode: 2021EGUGA..23..642Y Altcode: Magnetoseismology, a technique of magnetic field diagnostics based on observations of magnetohydrodynamic (MHD) waves, has been widely used to estimate the field strengths of oscillating structures in the solar corona. However, previously magnetoseismology was mostly applied to occasionally occurring oscillation events, providing an estimate of only the average field strength or one-dimensional distribution of field strength along an oscillating structure. This restriction could be eliminated if we apply magnetoseismology to the pervasive propagating transverse MHD waves discovered with the Coronal Multi-channel Polarimeter (CoMP). Using several CoMP observations of the Fe XIII 1074.7 nm and 1079.8 nm spectral lines, we obtained maps of the plasma density and wave phase speed in the corona, which allow us to map both the strength and direction of the coronal magnetic field in the plane of sky. We also examined distributions of the electron density and magnetic field strength, and compared their variations with height in the quiet Sun and active regions. Such measurements could provide critical information to advance our understanding of the Sun's magnetism and the magnetic coupling of the whole solar atmosphere. Title: Mapping solar magnetic fields from the photosphere to the base of the corona Authors: Ishikawa, Ryohko; Bueno, Javier Trujillo; del Pino Alemán, Tanausú; Okamoto, Takenori J.; McKenzie, David E.; Auchère, Frédéric; Kano, Ryouhei; Song, Donguk; Yoshida, Masaki; Rachmeler, Laurel A.; Kobayashi, Ken; Hara, Hirohisa; Kubo, Masahito; Narukage, Noriyuki; Sakao, Taro; Shimizu, Toshifumi; Suematsu, Yoshinori; Bethge, Christian; De Pontieu, Bart; Dalda, Alberto Sainz; Vigil, Genevieve D.; Winebarger, Amy; Ballester, Ernest Alsina; Belluzzi, Luca; Štěpán, Jiří; Ramos, Andrés Asensio; Carlsson, Mats; Leenaarts, Jorrit Bibcode: 2021SciA....7.8406I Altcode: 2021arXiv210301583I Routine ultraviolet imaging of the Sun's upper atmosphere shows the spectacular manifestation of solar activity; yet we remain blind to its main driver, the magnetic field. Here we report unprecedented spectropolarimetric observations of an active region plage and its surrounding enhanced network, showing circular polarization in ultraviolet (Mg II $h$ & $k$ and Mn I) and visible (Fe I) lines. We infer the longitudinal magnetic field from the photosphere to the very upper chromosphere. At the top of the plage chromosphere the field strengths reach more than 300 gauss, strongly correlated with the Mg II $k$ line core intensity and the electron pressure. This unique mapping shows how the magnetic field couples the different atmospheric layers and reveals the magnetic origin of the heating in the plage chromosphere. Title: Calibration of the MaGIXS Experiment. I. Calibration of the X-Ray Source at the X-Ray and Cryogenic Facility Authors: Athiray, P. S.; Winebarger, Amy R.; Champey, Patrick; Kobayashi, Ken; Vigil, Genevieve D.; Haight, Harlan; Johnson, Steven; Bethge, Christian; Rachmeler, Laurel A.; Savage, Sabrina; Beabout, Brent; Beabout, Dyana; Hogue, William; Guillory, Anthony; Siler, Richard; Wright, Ernest; Kegley, Jeffrey Bibcode: 2020ApJ...905...66A Altcode: 2020arXiv201009823A The Marshall Grazing Incidence Spectrometer (MaGIXS) is a sounding rocket experiment that will observe the soft X-ray spectrum of the Sun from 24 to 6.0 Å (0.5-2.0 keV) and is scheduled for launch in 2021. Component- and instrument-level calibrations for the MaGIXS instrument are carried out using the X-ray and Cryogenic Facility (XRCF) at NASA Marshall Space Flight Center. In this paper, we present the calibration of the incident X-ray flux from the electron impact source with different targets at the XRCF using a CCD camera; the photon flux at the CCD was low enough to enable its use as a "photon counter," i.e., the ability to identify individual photon hits and calculate their energy. The goal of this paper is two-fold: (1) to confirm that the flux measured by the XRCF beam normalization detectors is consistent with the values reported in the literature and therefore reliable for MaGIXS calibration and (2) to develop a method of counting photons in CCD images that best captures their number and energy. Title: Global maps of the magnetic field in the solar corona Authors: Yang, Zihao; Bethge, Christian; Tian, Hui; Tomczyk, Steven; Morton, Richard; Del Zanna, Giulio; McIntosh, Scott W.; Karak, Bidya Binay; Gibson, Sarah; Samanta, Tanmoy; He, Jiansen; Chen, Yajie; Wang, Linghua Bibcode: 2020Sci...369..694Y Altcode: 2020arXiv200803136Y Understanding many physical processes in the solar atmosphere requires determination of the magnetic field in each atmospheric layer. However, direct measurements of the magnetic field in the Sun’s corona are difficult to obtain. Using observations with the Coronal Multi-channel Polarimeter, we have determined the spatial distribution of the plasma density in the corona and the phase speed of the prevailing transverse magnetohydrodynamic waves within the plasma. We combined these measurements to map the plane-of-sky component of the global coronal magnetic field. The derived field strengths in the corona, from 1.05 to 1.35 solar radii, are mostly 1 to 4 gauss. Our results demonstrate the capability of imaging spectroscopy in coronal magnetic field diagnostics. Title: Unfolding Overlapping Spectral Images to Determine the Plasma Velocity During a Solar Flare Authors: Treffner, B.; Winebarger, A. R.; Bethge, C.; Lee, K. S.; Savage, S. L. Bibcode: 2019AGUFMSH31C3322T Altcode: Spectroscopic images of the Sun can provide temperature and velocity information when monitoring and detecting solar flares. Solar Flares and the associated Coronal Mass Ejections (CMEs) can send fast moving charged particles directly into the path of Earth and impact space-borne instrumentation and astronauts. Strong CMEs can affect power grids on the surface of Earth. Therefore, there is significant interest and research is being conducted to try to predict these events. As most spectrometers have a comparatively small slit width to avoid overlapping spectral images, their field of view is limited and scanning slit spectrometers often miss rapidly evolving events such as flares. Slot spectrometers measure both the imaging and spectral information over a much larger field of view. However, in these "overlappogram" images, the spectral and spatial information is convolved, making the data difficult to interpret. Recently, a method to unfold slitless spectrometer data was developed for the COronal Spectroscopic Imager in the EUV (COSIE) instrument. Building upon this research, Extreme-ultraviolet Imaging Spectrometer (EIS) and Atmospheric Imaging Assembly (AIA) data are used to determine the best spatial, temperature, and velocity parameters for the preflare data inversion, or unfolding. These parameters are then applied to the flare data inversion with the goal of determining the velocity of the plasma involved in a solar flare. Title: The High-Resolution Coronal Imager, Flight 2.1 Authors: Rachmeler, Laurel A.; Winebarger, Amy R.; Savage, Sabrina L.; Golub, Leon; Kobayashi, Ken; Vigil, Genevieve D.; Brooks, David H.; Cirtain, Jonathan W.; De Pontieu, Bart; McKenzie, David E.; Morton, Richard J.; Peter, Hardi; Testa, Paola; Tiwari, Sanjiv K.; Walsh, Robert W.; Warren, Harry P.; Alexander, Caroline; Ansell, Darren; Beabout, Brent L.; Beabout, Dyana L.; Bethge, Christian W.; Champey, Patrick R.; Cheimets, Peter N.; Cooper, Mark A.; Creel, Helen K.; Gates, Richard; Gomez, Carlos; Guillory, Anthony; Haight, Harlan; Hogue, William D.; Holloway, Todd; Hyde, David W.; Kenyon, Richard; Marshall, Joseph N.; McCracken, Jeff E.; McCracken, Kenneth; Mitchell, Karen O.; Ordway, Mark; Owen, Tim; Ranganathan, Jagan; Robertson, Bryan A.; Payne, M. Janie; Podgorski, William; Pryor, Jonathan; Samra, Jenna; Sloan, Mark D.; Soohoo, Howard A.; Steele, D. Brandon; Thompson, Furman V.; Thornton, Gary S.; Watkinson, Benjamin; Windt, David Bibcode: 2019SoPh..294..174R Altcode: 2019arXiv190905942R The third flight of the High-Resolution Coronal Imager (Hi-C 2.1) occurred on May 29, 2018; the Sounding Rocket was launched from White Sands Missile Range in New Mexico. The instrument has been modified from its original configuration (Hi-C 1) to observe the solar corona in a passband that peaks near 172 Å, and uses a new, custom-built low-noise camera. The instrument targeted Active Region 12712, and captured 78 images at a cadence of 4.4 s (18:56:22 - 19:01:57 UT; 5 min and 35 s observing time). The image spatial resolution varies due to quasi-periodic motion blur from the rocket; sharp images contain resolved features of at least 0.47 arcsec. There are coordinated observations from multiple ground- and space-based telescopes providing an unprecedented opportunity to observe the mass and energy coupling between the chromosphere and the corona. Details of the instrument and the data set are presented in this paper. Title: Unfolding Overlapped Slitless Imaging Spectrometer Data for Extended Sources Authors: Winebarger, Amy R.; Weber, Mark; Bethge, Christian; Downs, Cooper; Golub, Leon; DeLuca, Edward; Savage, Sabrina; del Zanna, Giulio; Samra, Jenna; Madsen, Chad; Ashraf, Afra; Carter, Courtney Bibcode: 2019ApJ...882...12W Altcode: 2018arXiv181108329W Slitless spectrometers can provide simultaneous imaging and spectral data over an extended field of view, thereby allowing rapid data acquisition for extended sources. In some instances, when the object is greatly extended or the spectral dispersion is too small, there may be locations in the focal plane where emission lines at different wavelengths contribute. It is then desirable to unfold the overlapped regions in order to isolate the contributions from the individual wavelengths. In this paper, we describe a method for such an unfolding, using an inversion technique developed for an extreme ultraviolet imaging spectrometer and coronagraph named the COronal Spectroscopic Imager in the EUV (COSIE). The COSIE spectrometer wavelength range (18.6-20.5 nm) contains a number of strong coronal emission lines and several density sensitive lines. We focus on optimizing the unfolding process to retrieve emission measure maps at constant temperature, maps of spectrally pure intensity in the Fe XII and Fe XIII lines, and density maps based on both Fe XII and Fe XIII diagnostics. Title: CLASP2: The Chromospheric LAyer Spectro-Polarimeter Authors: McKenzie, D. E.; Ishikawa, R.; Trujillo Bueno, J.; Auchére, F.; Rachmeler, L. A.; Kubo, M.; Kobayashi, K.; Winebarger, A. R.; Bethge, C. W.; Narukage, N.; Kano, R.; Ishikawa, S.; de Pontieu, B.; Carlsson, M.; Yoshida, M.; Belluzzi, L.; Štěpán, J.; del Pino Alemán, T.; Alsina Ballester, E.; Asensio Ramos, A. Bibcode: 2019ASPC..526..361M Altcode: The hydrogen Lyman-α line at 121.6 nm and the Mg k line at 279.5 nm are especially relevant for deciphering the magnetic structure of the chromosphere since their line-center signals are formed in the chromosphere and transition region, with unique sensitivities to magnetic fields. We propose the Chromospheric LAyer Spectro-Polarimeter (CLASP2), to build upon the success of the first CLASP flight, which measured the linear polarization in H I Lyman-α. The existing CLASP instrument will be refitted to measure all four Stokes parameters in the 280 nm range, including variations due to the anisotropic radiation pumping, the Hanle effect, and the Zeeman effect. Title: Combining sparsity DEM inversions with event tracking for AIA data Authors: Bethge, Christian; Winebarger, Amy; Tiwari, Sanjiv Bibcode: 2018csc..confE.108B Altcode: We apply a modified event tracking code (ASGARD - Automated Selection and Grouping of events in AIA Regional Data) to the results from sparsity DEM inversions (Cheung et al, 2015) using AIA EUV data. Outputs are grouped regions (x/y/t) in multiple defined temperature bins that can then be correlated in space and time to track the thermal evolution of coronal structures. We show examples and an overview of the methodology. Title: Current State of UV Spectro-Polarimetry and its Future Direction Authors: Ishikawa, Ryohko; Sakao, Taro; Katsukawa, Yukio; Hara, Hirohisa; Ichimoto, Kiyoshi; Shimizu, Toshifumi; Kubo, Masahito; Auchere, Frederic; De Pontieu, Bart; Winebarger, Amy; Kobayashi, . Ken; Kano, Ryouhei; Narukage, Noriyuki; Trujillo Bueno, Javier; Song, Dong-uk; Manso Sainz, Rafael; Asensio Ramos, Andres; Leenaarts, Jorritt; Carlsson, Mats; Bando, Takamasa; Ishikawa, Shin-nosuke; Tsuneta, Saku; Belluzzi, Luca; Suematsu, Yoshinori; Giono, Gabriel; Yoshida, Masaki; Goto, Motoshi; Del Pino Aleman, Tanausu; Stepan, Jiri; Okamoto, Joten; Tsuzuki, Toshihiro; Uraguchi, Fumihiro; Champey, Patrick; Alsina Ballester, Ernest; Casini, Roberto; McKenzie, David; Rachmeler, Laurel; Bethge, Christian Bibcode: 2018cosp...42E1564I Altcode: To obtain quantitative information on the magnetic field in low beta regions (i.e., upper chromosphere and above) has been increasingly important to understand the energetic phenomena of the outer solar atmosphere such as flare, coronal heating, and the solar wind acceleration. In the UV range, there are abundant spectral lines that originate in the upper chromosphere and transition region. However, the Zeeman effect in these spectral lines does not give rise to easily measurable polarization signals because of the weak magnetic field strength and the larger Doppler broadening compared with the Zeeman effect. Instead, the Hanle effect in UV lines is expected to be a suitable diagnostic tool of the magnetic field in the upper atmospheric layers. To investigate the validity of UV spectro-polarimetry and the Hanle effect, the Chromospheric Lyman-Alpha Spectro-Polarimeter (CLASP), which is a NASA sounding- rocket experiment, was launched at White Sands in US on September 3, 2015. During its 5 minutes ballistic flight, it successfully performed spectro-polarimetric observations of the hydrogen Lyman-alpha line (121.57 nm) with an unprecedentedly high polarization sensitivity of 0.1% in this wavelength range. CLASP observed the linear polarization produced by scattering process in VUV lines for the first time and detected the polarization signals which indicate the operation of the Hanle effect. Following the success of CLASP, we are confident that UV spectro-polarimetry is the way to proceed, and we are planning the second flight of CLASP (CLASP2: Chromospheric LAyer SpectroPolarimeter 2). For this second flight we will carry out spectro-polarimetry in the Mg II h and k lines around 280 nm, with minimum modifications of the CLASP1 instrument. The linear polarization in the Mg II k line is induced by scattering processes and the Hanle effect, being sensitive to magnetic field strengths of 5 to 50 G. In addition, the circular polarizations in the Mg II h and k lines induced by the Zeeman effect can be measurable in at least plage and active regions. The combination of the Hanle and Zeeman effects could help us to more reliably infer the magnetic fields of the upper solar chromosphere. CLASP2 was selected for flight and is being developed for launch in the spring of 2019.Based on these sounding rocket experiments (CLASP1 and 2), we aim at establishing the strategy and refining the instrument concept for future space missions to explore the enigmatic atmospheric layers via UV spectro-polarimetry. Title: Linearity Analysis and Efficiency Testing of The Chromospheric Lyman-Alpha Spectro-Polarimeter (CLASP) Science Cameras for Flight Authors: Walker, S. C.; Rachmeler, L.; Winebarger, A. R.; Champey, P. R.; Bethge, C. Bibcode: 2017AGUFMSH51C2503W Altcode: To unveil the complexity of the solar atmosphere, measurement of the magnetic field in the upper chromosphere and transition region is fundamentally important, as this is where the forces transition from plasma to magnetic field dominated. Measurements of the field are also needed to shed light on the energy transport from the lower atmospheric regions to the corona beyond. Such an advance in heliospheric knowledge became possible with the first flight of the international solar sounding rocket mission, CLASP. For the first time, linear polarization was measured in H Lyman-Alpha at 121.60 nm in September 2015. For linear polarization measurements in this line, high sensitivity is required due to the relatively weak polarization signal compared to the intensity. To achieve this high sensitivity, a low-noise sensor is required with good knowledge of its characterization, including linearity. This work presents further refinement of the linearity characterization of the cameras flown in 2015. We compared the current from a photodiode in the light path to the digital response of the detectors. Pre-flight CCD linearity measurements were taken for all three flight cameras and calculations of the linear fits and residuals were performed. However, the previous calculations included a smearing pattern and a digital saturation region on the detectors which were not properly taken into account. The calculations have been adjusted and were repeated for manually chosen sub-regions on the detectors that were found not to be affected. We present a brief overview of the instrument, the calibration data and procedures, and a comparison of the old and new linearity results. The CLASP cameras will be reused for the successor mission, CLASP2, which will measure the Mg II h & k lines between 279.45 nm and 280.35 nm. The new approach will help to better prepare for and to improve the camera characterization for CLASP2. Title: Comparison of Solar Fine Structure Observed Simultaneously in Lyα and Mg II h Authors: Schmit, D.; Sukhorukov, A. V.; De Pontieu, B.; Leenaarts, J.; Bethge, C.; Winebarger, A.; Auchère, F.; Bando, T.; Ishikawa, R.; Kano, R.; Kobayashi, K.; Narukage, N.; Trujillo Bueno, J. Bibcode: 2017ApJ...847..141S Altcode: 2017arXiv170900035S The Chromospheric Lyman Alpha Spectropolarimeter (CLASP) observed the Sun in H I Lyα during a suborbital rocket flight on 2015 September 3. The Interface Region Imaging Telescope (IRIS) coordinated with the CLASP observations and recorded nearly simultaneous and co-spatial observations in the Mg II h and k lines. The Mg II h and Lyα lines are important transitions, energetically and diagnostically, in the chromosphere. The canonical solar atmosphere model predicts that these lines form in close proximity to each other and so we expect that the line profiles will exhibit similar variability. In this analysis, we present these coordinated observations and discuss how the two profiles compare over a region of quiet Sun at viewing angles that approach the limb. In addition to the observations, we synthesize both line profiles using a 3D radiation-MHD simulation. In the observations, we find that the peak width and the peak intensities are well correlated between the lines. For the simulation, we do not find the same relationship. We have attempted to mitigate the instrumental differences between IRIS and CLASP and to reproduce the instrumental factors in the synthetic profiles. The model indicates that formation heights of the lines differ in a somewhat regular fashion related to magnetic geometry. This variation explains to some degree the lack of correlation, observed and synthesized, between Mg II and Lyα. Our analysis will aid in the definition of future observatories that aim to link dynamics in the chromosphere and transition region. Title: Introduction of the ASGARD code (Automated Selection and Grouping of events in AIA Regional Data) Authors: Bethge, Christian; Winebarger, Amy; Tiwari, Sanjiv K.; Fayock, Brian Bibcode: 2017SPD....4810623B Altcode: We have developed the ASGARD code to automatically detect and group brightenings ("events") in AIA data. The event selection and grouping can be optimized to the respective dataset with a multitude of control parameters. The code was initially written for IRIS data, but has since been optimized for AIA. However, the underlying algorithm is not limited to either and could be used for other data as well.Results from datasets in various AIA channels show that brightenings are reliably detected and that coherent coronal structures can be isolated by using the obtained information about the start, peak, and end times of events. We are presently working on a follow-up algorithm to automatically determine the heating and cooling timescales of coronal structures. This will be done by correlating the information from different AIA channels with different temperature responses. We will present the code and preliminary results. Title: CLASP2: The Chromospheric LAyer Spectro-Polarimeter Authors: Rachmeler, Laurel; E McKenzie, David; Ishikawa, Ryohko; Trujillo Bueno, Javier; Auchère, Frédéric; Kobayashi, Ken; Winebarger, Amy; Bethge, Christian; Kano, Ryouhei; Kubo, Masahito; Song, Donguk; Narukage, Noriyuki; Ishikawa, Shin-nosuke; De Pontieu, Bart; Carlsson, Mats; Yoshida, Masaki; Belluzzi, Luca; Stepan, Jiri; del Pino Alemná, Tanausú; Ballester, Ernest Alsina; Asensio Ramos, Andres Bibcode: 2017SPD....4811010R Altcode: We present the instrument, science case, and timeline of the CLASP2 sounding rocket mission. The successful CLASP (Chromospheric Lyman-Alpha Spectro-Polarimeter) sounding rocket flight in 2015 resulted in the first-ever linear polarization measurements of solar hydrogen Lyman-alpha line, which is sensitive to the Hanle effect and can be used to constrain the magnetic field and geometric complexity of the upper chromosphere. Ly-alpha is one of several upper chromospheric lines that contain magnetic information. In the spring of 2019, we will re-fly the modified CLASP telescope to measure the full Stokes profile of Mg II h & k near 280 nm. This set of lines is sensitive to the upper chromospheric magnetic field via both the Hanle and the Zeeman effects. Title: CLASP2: The Chromospheric LAyer Spectro-Polarimeter Authors: Rachmeler, Laurel A.; McKenzie, D. E.; Ishikawa, R.; Trujillo-Bueno, J.; Auchere, F.; Kobayashi, K.; Winebarger, A.; Bethge, C.; Kano, R.; Kubo, M.; Song, D.; Narukage, N.; Ishikawa, S.; De Pontieu, B.; Carlsson, M.; Yoshida, M.; Belluzzi, L.; Stepan, J.; del Pino Alemán, T.; Alsina Ballester, E.; Asensio Ramos, A. Bibcode: 2017shin.confE..79R Altcode: We present the instrument, science case, and timeline of the CLASP2 sounding rocket mission. The successful CLASP (Chromospheric Lyman-Alpha Spectro-Polarimeter) sounding rocket flight in 2015 resulted in the first-ever linear polarization measurements of solar hydrogen Lyman-alpha line, which is sensitive to the Hanle effect and can be used to constrain the magnetic field and geometric complexity of the upper chromosphere. Ly-alpha is one of several upper chromospheric lines that contain magnetic information. In the spring of 2019, we will re-fly the modified CLASP telescope to measure the full Stokes profile of Mg II h & k near 280 nm. This set of lines is sensitive to the upper chromospheric magnetic field via both the Hanle and the Zeeman effects. Title: Magnetic fields of opposite polarity in sunspot penumbrae Authors: Franz, M.; Collados, M.; Bethge, C.; Schlichenmaier, R.; Borrero, J. M.; Schmidt, W.; Lagg, A.; Solanki, S. K.; Berkefeld, T.; Kiess, C.; Rezaei, R.; Schmidt, D.; Sigwarth, M.; Soltau, D.; Volkmer, R.; von der Luhe, O.; Waldmann, T.; Orozco, D.; Pastor Yabar, A.; Denker, C.; Balthasar, H.; Staude, J.; Hofmann, A.; Strassmeier, K.; Feller, A.; Nicklas, H.; Kneer, F.; Sobotka, M. Bibcode: 2016A&A...596A...4F Altcode: 2016arXiv160800513F Context. A significant part of the penumbral magnetic field returns below the surface in the very deep photosphere. For lines in the visible, a large portion of this return field can only be detected indirectly by studying its imprints on strongly asymmetric and three-lobed Stokes V profiles. Infrared lines probe a narrow layer in the very deep photosphere, providing the possibility of directly measuring the orientation of magnetic fields close to the solar surface.