Harmonic generation of gravitational wave induced Alfven waves

TL;DR

This paper investigates how gravitational waves from merging binary pulsars can excite nonlinear Alfven waves, leading to harmonic generation, and discusses potential observational signatures of this process.

Contribution

It derives a wave equation for nonlinear, dispersive Alfven waves excited by gravitational waves and analyzes the saturation of harmonic generation due to dispersive effects.

Findings

Significant wave steepening occurs due to weak dispersion.

Harmonic generation saturates because of dispersive effects.

Estimated spectrum suggests potential observability.

Abstract

Here we consider the nonlinear evolution of Alfven waves that have been excited by gravitational waves from merging binary pulsars. We derive a wave equation for strongly nonlinear and dispersive Alfven waves. Due to the weak dispersion of the Alfven waves, significant wave steepening can occur, which in turn implies strong harmonic generation. We find that the harmonic generation is saturated due to dispersive effects, and use this to estimate the resulting spectrum. Finally we discuss the possibility of observing the above process.