Comparison of Solar Fine Structure Observed Simultaneously in Ly α and Mg ii h
- Bay Area Environmental Research Institute, 625 2nd Street, Suite 209, Petaluma, CA 94952 (United States)
- Institute for Theoretical Astrophysics, University of Oslo, P.O. Box 1029, Blindern NO-0315 Oslo (Norway)
- Lockheed Martin Solar and Astrophysics Laboratory, Building 252, 3176 Porter Drive, Palo Alto, CA 94304 (United States)
- NASA Marshall Space Flight Center, ZP 13, Huntsville, AL 35812 (United States)
- Institut d’Astrophysique Spatiale, CNRS/Univ. Paris-Sud 11, Bâtiment 121, F-91405 Orsay (France)
- National Astronomical Observatory of Japan, National Institutes of Natural Sciences, 2-21-1 Osawa, Mitaka, Tokyo 181-8588 (Japan)
- Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency, 3-1-1 Yoshinodai, Chuo-ku, Sagamihara, Kanagawa 252-5210 (Japan)
- Instituto de Astrofísica de Canarias, E-38205 La Laguna, Tenerife (Spain)
The Chromospheric Lyman Alpha Spectropolarimeter (CLASP) observed the Sun in H i Ly α 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 Ly α 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 Ly α . Our analysis will aid in the definition of future observatories that aim to link dynamics in the chromosphere and transition region.
- OSTI ID:
- 22679789
- Journal Information:
- Astrophysical Journal, Vol. 847, Issue 2; Other Information: Country of input: International Atomic Energy Agency (IAEA); ISSN 0004-637X
- Country of Publication:
- United States
- Language:
- English
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