ALPS: The Arbitrary Linear Plasma Solver

TL;DR

ALPS is a parallelized numerical tool that accurately computes plasma dispersion relations in complex, relativistic, magnetized plasmas with multiple particle species and arbitrary distribution functions, aiding research in space and laboratory plasma physics.

Contribution

ALPS introduces a novel, flexible numerical approach for solving plasma dispersion relations in arbitrary, relativistic, magnetized plasmas with multiple species and distribution functions.

Findings

Successfully computes dispersion relations for various plasma distributions.

Demonstrates reliability through tests on stable and unstable plasma configurations.

Enables analysis of wave properties in non-equilibrium plasmas.

Abstract

The Arbitrary Linear Plasma Solver (ALPS) is a parallelised numerical code that solves the dispersion relation in a hot (even relativistic) magnetised plasma with an arbitrary number of particle species with arbitrary gyrotropic equilibrium distribution functions for any direction of wave propagation with respect to the background field. ALPS reads the background momentum distributions as tables of values on a $(p_{\perp},p_{\parallel})$ grid, where $p_{\perp}$ and $p_{\parallel }$ are the momentum coordinates in the directions perpendicular and parallel to the background magnetic field, respectively. We present the mathematical and numerical approach used by ALPS and introduce our algorithms for the handling of poles and the analytic continuation for the Landau contour integral. We then show test calculations of dispersion relations for a selection of stable and unstable configurations in Maxwellian, bi-Maxwellian, $\kappa$-distributed, and J\"uttner-distributed plasmas. These tests demonstrate that ALPS derives reliable plasma dispersion relations. ALPS will make it possible to determine the properties of waves and instabilities in the non-equilibrium plasmas that are frequently found in space, laboratory experiments, and numerical simulations.