Bursts of Radiation and Recoil Effects in Electromagnetism and Gravitation

TL;DR

This paper models impulsive accelerations in electromagnetism and gravitation, revealing radiation bursts and recoil effects, including electromagnetic bremsstrahlung and energy emission during mass deceleration.

Contribution

It provides explicit constructions of radiation effects in electromagnetism and gravitation using spacetime matching techniques, highlighting recoil phenomena and energy emission in impulsive events.

Findings

Impulsive acceleration causes electromagnetic radiation modeled as instantaneous bremsstrahlung.

Deceleration of a gravitating mass results in emission of a light-like shell with energy equal to the initial kinetic energy.

Recoil effects in gravity can be viewed as a limiting case of a Kinnersley rocket.

Abstract

The Maxwell field of a charge e which experiences an impulsive acceleration or deceleration is constructed explicitly by subdividing Minkowskian space-time into two halves bounded by a future null-cone and then glueing the halves back together with appropriate matching conditions. The resulting retarded radiation can be viewed as instantaneous electromagnetic bremsstrahlung. If we similarly consider a spherically symmetric, moving gravitating mass, to experience an impulsive deceleration, as viewed by a distant observer, then this is accompanied by the emission of a light-like shell whose total energy measured by this observer is the same as the kinetic energy of the source before it stops. This phenomenon is a recoil effect which may be thought of as a limiting case of a Kinnersley rocket.