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

Teyoun Kang, Adam Noble, Samuel R. Yoffe, Dino A. Jaroszynski, Min Sup Hur

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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.
Original languageEnglish
Article number127445
Number of pages5
JournalPhysics Letters A
Early online date20 May 2021
Publication statusE-pub ahead of print - 20 May 2021


  • radiation reaction
  • uniform acceleration
  • electrodynamics

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