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Macroscopic quasi‐linear theory and particle‐in‐cell simulation of helium ion anisotropy instabilities
Author(s) -
Yoon Peter H.,
Seough Jungjoon,
Hwang Junga,
Nariyuki Yasuhiro
Publication year - 2015
Publication title -
journal of geophysical research: space physics
Language(s) - English
Resource type - Journals
eISSN - 2169-9402
pISSN - 2169-9380
DOI - 10.1002/2015ja021495
Subject(s) - anisotropy , physics , particle in cell , wave–particle duality , helium , instability , ion , nonlinear system , particle (ecology) , proton , computational physics , mechanics , atomic physics , plasma , quantum mechanics , oceanography , geology
The protons and helium ions in the solar wind are observed to possess anisotropic temperature profiles. The anisotropy appears to be limited by various marginal instability conditions. One of the efficient methods to investigate the global dynamics and distribution of various temperature anisotropies in the large‐scale solar wind models may be that based upon the macroscopic quasi‐linear approach. The present paper investigates the proton and helium ion anisotropy instabilities on the basis of the quasi‐linear theory versus particle‐in‐cell simulation. It is found that the overall dynamical development of the particle temperatures is quite accurately reproduced by the macroscopic quasi‐linear scheme. The wave energy development in time, however, shows somewhat less restrictive comparisons, indicating that while the quasi‐linear method is acceptable for the particle dynamics, the wave analysis probably requires higher‐order physics, such as wave‐wave coupling or nonlinear wave‐particle interaction.