Abstract:
Three different levels of description are available to describe the interaction of electromagnetic radiation with electrons in a fully ionized plasma: stimulated Raman scattering, stimulated Compton scattering, and Compton scattering. The scattering rates in each case differ significantly. The physics of these mechanisms is illustrated by taking a quasar as the source of intense radiation and the hot plasma surrounding it as the scattering medium. It is concluded that, through Raman scattering, the non-thermal radio radiation equilibrates with the intercloud medium at much higher temperatures than are achievable through Compton processes.