Temperature Relaxation Rates in Strongly Magnetized Plasmas

Fuente: arXiv
Saved in:
Bibliographic Details
Main Authors: Jose, Louis, Welch III, James C., Tharp, Timothy D., Baalrud, Scott D.
Format: Preprint
Published: 2024
Subjects:
Online Access:
Tags: Add Tag
No Tags, Be the first to tag this record!
_version_ 1866912113217241088
author Jose, Louis
Welch III, James C.
Tharp, Timothy D.
Baalrud, Scott D.
author_facet Jose, Louis
Welch III, James C.
Tharp, Timothy D.
Baalrud, Scott D.
contents Strongly magnetized plasmas, characterized by having a gyrofrequency larger than the plasma frequency ($β= ω_c/ω_p \gg 1$), are known to exhibit novel transport properties. Previous works studying pure electron plasmas have shown that strong magnetization significantly inhibits energy exchange between parallel and perpendicular directions, leading to a prolonged time for relaxation of a temperature anisotropy. Recent work studying repulsive electron-ion interactions showed that strong magnetization increases both the parallel and perpendicular temperature relaxation rates of ions, but in differing magnitudes, resulting in the formation of temperature anisotropy during equilibration. This previous study treated electrons as a heat bath and assumed weak magnetization of ions. Here, we broaden this analysis and compute the full temperature and temperature anisotropy evolution over a broad range of magnetic field strengths. It is found that when electrons are strongly magnetized ($β_e \gg 1$) and ions are weakly magnetized ($β_i \ll 1$), the magnetic field strongly suppresses the perpendicular energy exchange rate of electrons, whereas the parallel exchange rate slightly increases in magnitude compared to the value at weak magnetization. In contrast, the ion perpendicular and parallel energy exchange rates both increase in magnitude compared to the values at weak magnetization. Consequently, equilibration causes the electron parallel temperature to rapidly align with the ion temperature, while the electron perpendicular temperature changes much more slowly. It is also shown that when both ions and electrons are strongly magnetized ($β_i, β_e \gg 1$) the ion-electron perpendicular relaxation rate dramatically decreases with magnetization strength as well.
format Preprint
id arxiv_https___arxiv_org_abs_2411_06521
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Temperature Relaxation Rates in Strongly Magnetized Plasmas
Jose, Louis
Welch III, James C.
Tharp, Timothy D.
Baalrud, Scott D.
Plasma Physics
Strongly magnetized plasmas, characterized by having a gyrofrequency larger than the plasma frequency ($β= ω_c/ω_p \gg 1$), are known to exhibit novel transport properties. Previous works studying pure electron plasmas have shown that strong magnetization significantly inhibits energy exchange between parallel and perpendicular directions, leading to a prolonged time for relaxation of a temperature anisotropy. Recent work studying repulsive electron-ion interactions showed that strong magnetization increases both the parallel and perpendicular temperature relaxation rates of ions, but in differing magnitudes, resulting in the formation of temperature anisotropy during equilibration. This previous study treated electrons as a heat bath and assumed weak magnetization of ions. Here, we broaden this analysis and compute the full temperature and temperature anisotropy evolution over a broad range of magnetic field strengths. It is found that when electrons are strongly magnetized ($β_e \gg 1$) and ions are weakly magnetized ($β_i \ll 1$), the magnetic field strongly suppresses the perpendicular energy exchange rate of electrons, whereas the parallel exchange rate slightly increases in magnitude compared to the value at weak magnetization. In contrast, the ion perpendicular and parallel energy exchange rates both increase in magnitude compared to the values at weak magnetization. Consequently, equilibration causes the electron parallel temperature to rapidly align with the ion temperature, while the electron perpendicular temperature changes much more slowly. It is also shown that when both ions and electrons are strongly magnetized ($β_i, β_e \gg 1$) the ion-electron perpendicular relaxation rate dramatically decreases with magnetization strength as well.
title Temperature Relaxation Rates in Strongly Magnetized Plasmas
topic Plasma Physics
url https://arxiv.org/abs/2411.06521