A search for hard X-ray microflares near solar minimum |
| |
| Authors: | R P Lin K C Hurley D M Smith R M Pelling |
| |
| Institution: | (1) Space Sciences Laboratory, University of California, 94720 Berkeley, CA, U.S.A.;(2) Center for Astrophysics and Space Science, University of California, San Diego, U.S.A. |
| |
| Abstract: | Near solar maximum, hard X-ray microflares with peak 20 keV fluxes of  10–2 (cm2 s keV)–1, more than ten times smaller than for typical flares and subflares, can occur at the rate of about once every five minutes. We report here on a search for hard X-ray microflares made on a long duration balloon flight in February 1987 near solar minimum, at a time when no active regions were on the Sun. No microflares were observed over a total observing time of 16.5 hours spread over three days, implying a statistical upper limit to their rate of occurrence about a factor often lower than observed near solar maximum. Thus hard X-ray microflaring appears to be an active region phenomenon, and apparently not associated with flaring of soft X-ray bright points. |
| |
| Keywords: | |
| 本文献已被 SpringerLink 等数据库收录！ |
|
