Numerical study of the upstream wave excitation mechanism: 1. Nonlinear phase bunching of beam ions

• Main Authors: Hoshino,Masahiro, Terasawa,Toshio
• Format: Report
• Language: English
• Published: Institute of Space and Astronautical Science/Institute of Space and Astronautical Science 1985
• Subjects: Memoirs of National Institute of Polar Research; Polar Research
• Online Access: https://nipr.repo.nii.ac.jp/?action=repository_uri&item_id=1769; http://id.nii.ac.jp/1291/00001769/; https://nipr.repo.nii.ac.jp/?action=repository_action_common_download&item_id=1769&item_no=1&attribute_id=18&file_no=1

By means of the particle simulation, we study the excitation mechanism of low frequency (0.01-0.05Hz) upstream hydromagnetic waves. Initially, we observe excitation of the right-hand polarized waves propagating parallel to the field-aligned ion beam, which is given as the free energy source. In the nonlinear stage, we observed the phase space bunching of beam ions by the excited waves. We apply this bunching effect to the explanation of 'gyrophased bunched' ions observed in the foreshock region.