Temperature Anisotropy Instabilities Stimulated by the Solar Wind Suprathermal Populations

Frontiers in Astronomy and Space Sciences

Astronomy and Space Sciences

Marian Lazar¹  Stefaan Poedts²  R.A. López³  Horst Fichtner⁴  Peter Haesung Yoon⁵  Shaaban Mohammed Shaaban⁶ 

[1] Centre for Mathematical Plasma-Astrophysics, KU Leuven, Leuven, Belgium;Institut für Theoretische Physik IV, Ruhr-Universität Bochum, Bochum, Germany;Centre for Mathematical Plasma-Astrophysics, KU Leuven, Leuven, Belgium;Institute of Physics, University of Maria Curie-Skłodowska, Lublin, Poland;Departamento de Física, Universidad de Santiago de Chile, Santiago, Chile;Institut für Theoretische Physik IV, Ruhr-Universität Bochum, Bochum, Germany;Institute for Physical Science and Technology, University of Maryland, College Park, MD, United States;Theoretical Physics Research Group, Physics Department, Faculty of Science, Mansoura University, Mansoura, Egypt;

关键词: instabilities;    solar wind;    temperature;    suprathermal particles;    particle velocity distribution;   

DOI  :  10.3389/fspas.2021.777559

 received in 2021-09-15, accepted in 2021-12-14,  发布年份 2022

来源: Frontiers

【 摘 要 】

This review paper compiles recent results obtained by the present group of authors describing the effects of suprathermal populations present in space plasmas (up to a few keVs) on temperature anisotropy instabilities. Of particular interest are the electromagnetic cyclotron and firehose excitations, which play a major role in limiting temperature anisotropy, resulting, for instance, from the adiabatic expansion of the solar wind. Relying on a rigorous modeling and interpretation of the observed velocity distributions, both theoretical models and numerical simulations indicate a systematic stimulation of these excitations in the presence of suprathermal populations of electrons or protons. Moreover, the enhanced fluctuations react back on particles, and determine a faster and deeper relaxation of their anisotropy. The present comparative analysis suggests that previous studies, considering only quasi-thermal low-energy populations, may have significantly underestimated these excitations and their implications in various applications in space plasmas.

【 授权许可】

Unknown   
Copyright © 2022 Lazar, López, Shaaban, Poedts, Yoon and Fichtner.