The solar hydrogen Lyman alpha to Lyman beta line ratio
|Titre||The solar hydrogen Lyman alpha to Lyman beta line ratio|
|Type de publication||Journal Article|
|Year of Publication||2012|
|Auteurs||Lemaire, P, Vial, JC, Curdt, W, Schühle, U, Woods, TN|
|Journal||Astronomy & Astrophysics|
Aims. We investigate the variation in the solar hydrogen Lyman alpha (Ly alpha) to Lyman beta (Ly beta) line ratio as a function of the solar activity by taking into account new results obtained by SoHO/SUMER and TIMED/SEE. Methods. We reanalyze data of quiet and active regions previously collected with the LPSP multichannel instrument on OSO8. We then re-examine data obtained on the solar disk with SUMER and compare them with previous data. In a second step, we use the full Sun H I Ly beta profiles to determine the Ly beta contribution to the SEE profiles obtained with a 0.4 nm full width at half-maximum. The variation in the Ly alpha to Ly beta line ratio is then measured for part of the solar cycle 23 (2002-2008). Results. We determine the radiance line ratio of the solar H I Ly alpha to Ly beta line for a quiet Sun area and the relation between the ratio of the Ly alpha to Ly beta irradiance and the Ly alpha solar irradiance.