Occurrence Rate of X-Ray Plasma Ejections

Masamitsu Ohyama

Abstract

Yohkoh discovered X-ray plasma (plasmoid) ejections in many impulsive and LDE flares. We examine 126 limb flares between October 1991 and August 1998. X-ray plasma ejections are found in 54 flares. All X-ray plasmoids are detected in images taken before the maximum peak of hard X-ray (HXR) emission or in each first image after the HXR peak. If we choose 57 flares which soft X-ray telescope aboard Yohkoh started to observe before the HXR peak, X-ray plasma ejections are found in 63--70 % of these flares. >From this result We propose that X-ray plasma ejection is a general phenomenon associated with a solar flare.

Authors: Masamitsu Ohyama and Kazunari Shibata

Organization: University of Maryland / Kwasan Observatory, Kyoto
Univ.
     Telephone: 301-405-6048
           Fax: 301-314-9067
        e-mail: ohyama@astro.umd.edu
       Address: Department of Astronomy
   University of Maryland
   College Park , Maryland 20742, U.S.A.