135 / 2023-04-14 16:12:47

Interparticle Fields and Collective Radiation Reaction

Radiation Reaction,Coherent radiation,plasma,electron-positron,collective effects

极端光下的基础物理学 > QED效应和核物理-II

In classical electrodynamics, energy losses due to the emission of electromagnetic radiation can be accounted for by solving the Landau-Lifshitz equation of motion. For many particles in an external field, this equation is often solved analytically while treating each particle independently. Numerical solutions may also include a self-consistent mean field, while interparticle fields are typically ignored. By considering the collision of a neutral, relativistic electron-positron bunch with an intense laser pulse, we demonstrate the inclusion of interparticle fields when solving the LL equation can coherently amplify a broad range of radiated frequencies, by orders of magnitude. This corresponds to an inhomogeneous energy loss by particles within the bunch, which cannot be seen if interparticle fields are ignored. A similar mechanism might affect the dynamics of electron-positron bunches around compact astrophysical objects, which are suggested to account for coherent radio emission and fast radio bursts. This implies a microscopic understanding of coherence mechanisms and collective radiation reaction is essential.