Upshifted frequency of electromagnetic plasma waves due to reflecting gravitational waves acting as almost-luminal mirrors

TL;DR

This paper demonstrates that dispersive gravitational waves can act as near-luminal mirrors in a plasma, reflecting electromagnetic waves and causing an upshift in their frequency, especially for low-frequency incident waves.

Contribution

It introduces a novel mechanism where gravitational waves reflect electromagnetic waves in plasma, leading to frequency upshifts, which was not previously understood.

Findings

Gravitational waves can reflect electromagnetic waves in plasma.

Reflected waves experience frequency upshift, more pronounced at low incident frequencies.

The effect occurs when gravitational waves propagate near the speed of light.

Abstract

We show that dispersive gravitational waves, as a background spacetime, can reflect electromagnetic waves in a plasma. This reflection upshifts the frequency of the reflected wave, being larger for low-frequency incident waves. This effect takes place when the gravitational wave background propagates almost at the speed of light, allowing it to behave similar to a luminal mirror to electromagnetic plasma waves.