# Temperature-dependent Saturation of Weibel-type Instabilities in Counter-streaming Plasmas

## TL;DR

This study uses advanced simulations to show that the temperature of counter-streaming plasmas significantly affects the saturation and magnetic field generation of Weibel-type instabilities, impacting astrophysical and laboratory plasma magnetization.

## Contribution

First 2X2V continuum Vlasov-Maxwell simulations reveal temperature-dependent saturation effects in Weibel instabilities in counter-streaming plasmas.

## Key findings

- Colder plasmas exhibit significantly reduced temperature anisotropy.
- Magnetization levels are orders of magnitude lower in colder plasmas.
- Energy conversion efficiency depends strongly on plasma temperature.

## Abstract

We present the first 2X2V continuum Vlasov-Maxwell simulations of interpenetrating, unmagnetized plasmas to study the competition between two-stream, Oblique, and filamentation modes in the weakly relativistic regime. We find that after nonlinear saturation of the fastest-growing two-stream and Oblique modes, the effective temperature anisotropy, which drives current filament formation via the secular Weibel instability, has a strong dependence on the internal temperature of the counter-streaming plasmas. The effective temperature anisotropy is significantly more reduced in colder than in hotter plasmas, leading to orders of magnitude lower magnetization for colder plasmas. A strong dependence of the energy conversion efficiency of Weibel-type instabilities on internal beam temperature has implications for determining their contribution to the observed magnetization of many astrophysical and laboratory plasmas.