Resonant interaction between gravitational waves, electromagnetic waves and plasma flows

TL;DR

This paper derives and solves equations describing how gravitational, electromagnetic waves, and plasma flows interact in magnetized plasmas, revealing energy exchange mechanisms, instabilities, and potential astrophysical implications.

Contribution

It introduces a comprehensive analytical framework for wave interactions in magnetized plasmas, including effects of plasma drift flows, and identifies conditions for instabilities and wave generation.

Findings

Analytical solutions for wave interaction equations.

Identification of explosive instabilities with drift flows.

Conditions for wave-induced particle acceleration.

Abstract

In magnetized plasmas gravitational and electromagnetic waves may interact coherently and exchange energy between themselves and with plasma flows. We derive the wave interaction equations for these processes in the case of waves propagating perpendicular or parallel to the plasma background magnetic field. In the latter case, the electromagnetic waves are taken to be circularly polarized waves of arbitrary amplitude. We allow for a background drift flow of the plasma components which increases the number of possible evolution scenarios. The interaction equations are solved analytically and the characteristic time scales for conversion between gravitational and electromagnetic waves are found. In particular, it is shown that in the presence of a drift flow there are explosive instabilities resulting in the generation of gravitational and electromagnetic waves. Conversely, we show that energetic waves can interact to accelerate particles and thereby \emph{produce} a drift flow. The relevance of these results for astrophysical and cosmological plasmas is discussed.