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arXiv · 1002.3551

Hydrogen Lyman emission through the solar cycle

W. Curdt·H. Tian
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Abstract

We present observations and results of radiance and irradiance studies completed by SoHO-SUMER during the past solar cycle. We find that the cycle variation in Ly-alpha irradiance as observed by e.g. UARS-SOLSTICE can not be explained by quiet sun radiance data, and conclude that the explanation must be related to differences in the Ly-alpha radiance of various solar features and changes in their fractional distribution over the solar cycle. Consequently, we studied the emission of the hydrogen Ly-alpha line in various solar features - for the first time observed by SUMER on disk in full resolution - to investigate the imprint of the magnetic field on line profile and radiance distribution. We also compare quasi-simultaneous Ly-alpha and Ly-beta line profiles. Such high-resolution observations - not hampered by geocoronal absorption - have never been completed before.

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W. Curdt, H. Tian. 2010-02-18. Hydrogen Lyman emission through the solar cycle. https://arxiv.org/abs/1002.3551

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