AC Currents from Gravitational Waves in Plasma Flows

TL;DR

This paper explores how gravitational waves can induce AC currents in plasmas with background currents, revealing that anisotropic plasmas can generate secondary currents inheriting the gravitational wave frequency.

Contribution

It introduces the novel idea that gravitational waves can induce AC currents in anisotropic plasmas with background currents, expanding understanding beyond the Gertsenshtein effect.

Findings

In isotropic plasmas, no secondary perturbations occur.

Anisotropic plasmas with background currents can produce secondary AC currents.

Secondary currents inherit the gravitational wave frequency.

Abstract

It is well-known that gravitational waves can induce electromagnetic perturbations in magnetised plasmas, with production occurring via the direct coupling of gravitational waves to the background magnetic field: this is the so-called Gertsenshtein effect. In this short work, we consider the direct gravitational perturbations of charge carriers via their minimal coupling to gravity in a collisionless plasma. We find that for isotropic plasmas, no secondary plasma perturbations are generated. However, when an anisotropy is introduced in the form of a background plasma current, we find that gravitational waves can induce a secondary current. For a constant DC background current, the secondary current inherits the AC frequency of the gravitational waves. It will certainly be interesting to investigate this effect in astrophysical plasmas in future work as well as its wider phenomenological consequences.