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Paper: Hydrogen Lyman Emission through the Solar Cycle
Volume: 428, SOHO-23: Understanding a Peculiar Solar Minimum
Page: 81
Authors: Curdt, W.; Tian, H.
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-α irradiance as observed by, e.g., UARS/SOLSTICE cannot be explained by quiet Sun radiance data, and conclude that the explanation must be related to differences in the Ly-α radiance of various solar features and changes in their fractional distribution over the solar cycle. Consequently, we studied the emission of the hydrogen Ly-α 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-α and Ly-β line profiles. Such high-resolution observations—not hampered by geocoronal absorption—have never been completed before.
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