Energetic Particles and High-Energy Solar Phenomena

Abstract

Solar flares generally occur in association with rapid change of sunspot magnetic fields in time and space. A typical flare is accompanied by high-energy phenomena such as non-thermal emissions of gamma-rays, hard and soft X-rays and radio waves of wide frequency band. Large solar flares are often accompanied by both emissions of high-energy photons and accelerated particles (electrons, protons, and heavier nuclei). Non-thermal photon emissions are produced mostly by high-energy electrons and protons as a result of their interaction with plasmas and magnetic fields in the solar atmosphere. To understand the emission mechanism of these high-energy photons on the Sun, it is, therefore, necessary to find the acceleration mechanism for both nuclei and electrons. A part of the accelerated nuclei and electrons are later released from the solar atmosphere. Their behaviour in the interplanetary space is considered to be closely linked with the large-scale structure of magnetic fields in the inner Solar system.