Velocity distribution function anisotropy of soft X-ray generated photoelectrons and resulting H polarization in solar flares
J.-C. Hénoux 1 and
M. Karlický 2
Received 14 August 1998 / Accepted 27 October 1998
Soft X-rays irradiation of the solar atmosphere during solar flares generates photoelectrons which have an anisotropic velocity distribution. Using a 1-D test particle code, the anisotropy of the photoelectrons velocity distribution is derived, and the maximum degree of linear polarization in the hydrogen H and H lines that photoelectrons could generate by impact is estimated. Over a band pass of 0.75 and 0.5 Å, the net polarization degree expected in both lines is predicted not to exceed 0.2%. Therefore, soft X-ray irradiation cannot explain the one order of magnitude higher degree of linear polarization observed in solar flares.
Key words: line: formation polarization Sun: flares Sun: particle emission Sun: X-rays, gamma rays
Send offprint requests to: J.C. Hénoux
Correspondence to: J.C. Hénoux
This article contains no SIMBAD objects.
© European Southern Observatory (ESO) 1999
Online publication: December 16, 1998