Some Radiation ProbleMS in Electrodynamics and Gravity

Abstract

An accelerated charged particle radiates according to the Classical Electrodynamics. In standard literature, the dynamics of an accelerated charged particle is described by introducing a `radiation reaction force' i.e. by resorting to the Lorentz-Abraham-Dirac (LAD) equation of motion. However, it is clear that the LAD equation of motion give pathological solutions even in the simplest case. Many alternate possibilities are discussed in literature. However, these remedies are not successful in eradicating these issues. Here we approach this issue from energy conservation point of view. Using simple energy conservation relation we derive the equation of motion to describe the dynamics of accelerating charged particle. To the point we have explored it in few cases, we find our equation of motion free of any unphysical solutions. A similar situation arises in Gravity due to emission of gravitational waves. We extend our idea to write the equation of motion in this case. Further, we study the `Unruh Effect' which states that an accelerating detector in flat Minkowski spacetime vacuum would find itself in a thermal bath which has a temperature proportional to its acceleration. Our aim is to consolidate various ideas presented in literature on this issue so that it can serve as a good starting point for further research on the connection between these phenomena.