小さい高エネルギーフレアにおけるX型電流ループ合体による粒子加速

摘要

We studied the acceleration conditions in the small but fairly energetic flare of May 21, 1984 at 13:26 UT. The most pronounced aspect of this flare was a series of 13 microwave / x-ray spikes, each lasting for about 0.1s. A previous study has shown that each of these was due to a series of successive sudden formations of small plasma knots of high energy particles. Each of these knots lost its energy in about 50 ms. In the present study we show that these knots can originate by the process of x-type (3-D) flux tube coalescence. The predicted rise time (30 to 50 ms) and energy are in good agreement with the observationally derived parameters.