Radiation reaction and the acceleration-dependent mass increase of a charged sphere undergoing uniform acceleration

• Published in: Physics letters. A 2021-08, Vol.407, p.127445, Article 127445
• Main Authors: Kang, Teyoun, Noble, Adam, Yoffe, Samuel R., Jaroszynski, Dino A., Hur, Min Sup
• Format: Article
• Language: English
• Subjects: Electrodynamics; Radiation reaction; Uniform acceleration
• ISSN: 0375-9601; 1873-2429
• DOI: 10.1016/j.physleta.2021.127445

•Many theories have predicted that a uniformly accelerated point charge feels no radiation reaction.•It is shown that a particle of finite size can feel the reaction, by the increase of the particle's effective mass.•The mass increase is proportional to a new factor γa, which only depends on the size and acceleration of the particle.•It means that more energy should be provided to the particle, in order to get the expected acceleration.•This extra energy compensates for the energy loss by radiation. Photon emission from a uniformly accelerated charge is among the most mysterious physical phenomena. Theories based on the Lorentz-Abraham-Dirac equation mostly conclude that a uniformly accelerated point charge cannot feel radiation reaction. Such a conclusion suggests that the origin of the photon energy is unclear. In this paper, we determine the self-force of a uniformly accelerated charged sphere using the Lorentz force equation, with an assumption that the sphere is Lorentz-contracted during the acceleration. For large acceleration, the calculated self-force converges to the radiation reaction (given by the Larmor formula) via a new factor γa, which describes an acceleration-dependent increase in the effective mass. This increased mass makes it harder to accelerate the particle (compared to a point-charge), which means more energy should be provided to the particle in order to get the expected acceleration. This extra energy can be interpreted as the origin of the photon energy.