# Relaxed States in Relativistic Multi-Fluid Plasmas

## TL;DR

This paper derives evolution equations for relativistic multi-fluid plasmas, introduces a generalized vorticity framework, and explores relaxed equilibrium states using a variational principle, providing insights into plasma stability and structure.

## Contribution

It presents a minimal fluid coupling model for relativistic plasmas, casting evolution equations in terms of generalized vorticity, and identifies relaxed states via a variational approach.

## Key findings

- Equations for relativistic multi-fluid plasmas are derived.
- Relaxed states are characterized as minima of enstrophy with energy and helicity constraints.
- Example solutions illustrate the structure of these relaxed states.

## Abstract

The evolution equations for a plasma comprising multiple species of charged fluids with relativistic bulk and thermal motion are derived. It is shown that a minimal fluid coupling model allows a natural casting of the evolution equations in terms of generalized vorticity which treats the fluid motion and electromagnetic fields equally. Equilibria can be found using a variational principle based on minimizing the total enstrophy subject to energy and helicity constraints. A subset of these equilibria correspond to minimum energy. The equations for these states are presented with example solutions showing the structure of the relaxed states.