Dissipation and particle energization in moderate to low beta turbulent plasma via PIC simulations

11th International Conference on Numerical Modeling of Space Plasma Flows

Makwana, Kirit^1 ; Li, Hui^2 ; Guo, Fan^2 ; Li, Xiaocan^3

Center for Mathematical Plasma Astrophysics, KU Leuven, Belgium^1

Los Alamos National Laboratory, NM, United States^2

University of Alabama-Huntsville, Alabama, United States^3

关键词: Decaying turbulence;    Electron-positron pairs;    Energy decay rates;    Magnetic pressure;    Magnetic reconnections;    Particle kinetic energy;    Particle-in-cell code;    Perpendicular wave numbers;   

Others  :  https://iopscience.iop.org/article/10.1088/1742-6596/837/1/012004/pdf
DOI  :  10.1088/1742-6596/837/1/012004

来源: IOP

【 摘 要 】

We simulate decaying turbulence in electron-positron pair plasmas using a fully-kinetic particle-in-cell (PIC) code. We run two simulations with moderate-to-low plasma β (the ratio of thermal pressure to magnetic pressure). The energy decay rate is found to be similar in both cases. The perpendicular wave-number spectrum of magnetic energy shows a slope between and , where the perpendicular (⊥) and parallel () directions are defined with respect to the magnetic field. The particle kinetic energy distribution function shows the formation of a non-thermal feature in the case of lower plasma β, with a slope close to E-1. The correlation between thin turbulent current sheets and Ohmic heating by the dot product of electric field (E) and current density (J) is investigated. Heating by the parallel E• Jterm dominates the perpendicular E⊥• J⊥term. Regions of strong E• Jare spatially well-correlated with regions of intense current sheets, which also appear correlated with regions of strong Ein the low β simulation, suggesting an important role of magnetic reconnection in the dissipation of low β plasma turbulence.