JapaneseGEMSIS-Sun
Drift-Kinetic Modeling of Particle Acceleration and Transport in Solar Flares
We developed a numerical model based on the drift-kinetic theory in order to understand particle acceleration and transport in solar flares. The model identified two dominant mechanisms of electron acceleration: betatron acceleration at the top of closed loops and inertia drift acceleration in open magnetic field lines. The number of accelerated electrons in open-field lines estimated from the model is comparable to observations of electrons escaping from the Sun to interplanetary space. Using this model, we investigated the effect of pitch-angle scattering on the electron distribution. When the scattering is involved, the peak heights of the electrons depend on the energy; the intermediate-energy electrons are at a higher altitude, whereas the lower and higher energy electrons inhabit lower altitudes. This result is interpreted as follows: pitch-angle scattering at intermediate energy causes efficient precipitation into the footpoint and a resulting loss from the loop in the course of the loop shrinkage. This result can explain the position of the ¨above-the-loop-top¨ hard X-ray source.