Micro to mesoscale structures of the heliospheric termination shock and the associated particle acceleration

2015 Fiscal Year Final Research Report

• Project/Area Number: 25400479
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Research Field: Space and upper atmospheric physics
• Research Institution: Kyushu University
• Principal Investigator: Matsukiyo Shuichi 九州大学, 総合理工学研究科(研究院), 助教 (00380709)
• Project Period (FY): 2013-04-01 – 2016-03-31
• Keywords: 太陽圏終端衝撃波 / 粒子加速 / 数値シミュレーション / ピックアップイオン

Outline of Final Research Achievements

Full particle-in-cell simulations, known as a first principle simulation method of collisionless plasmas, are used to reproduce the heliospheric termination shock and to examine micro- to meso-scale structures of the shock transition region and their effects on particle acceleration processes.
In terms of ion acceleration, shock surfing acceleration (SSA) model had been a most plausible model as the mechanism of initial acceleration of anomalous cosmic rays which were believed to be accelerated at the termination shock. This study revealed that the SSA does not work if the presence of right amount of pickup ions are taken into account. Instead, it was shown that shock drift acceleration is a more plausible mechanism. Electron acceleration at the termination shock, on the other hand, had not been strenuously discussed. Here, it was demonstrated that wave-particle interactions through the multi-scale structures in the transition region result in locally producing non-thermal electrons.

Free Research Field

宇宙プラズマ物理学