A study is made of the interaction of a random field of electromagnetic radiation with the free electrons of a plasma, with applications to astrophysical problems, in particular the theory of how thermodynamic equilibrium of the radiation in a hot universe is established. A kinetic equation describes the variation of the spectrum; special attention is devoted to induced scattering and the classical interpretation of induced energy and momentum transfer. In the spectra of radio sources with a high luminosity temperature, induced scattering can lead to a Bose condensation of photons, a shock wave and solitons. The scattering of strong low-frequency waves is considered in connection with their effect on pulsars and laboratory coherent generators.

@article{Zel’dovich:1975,
	author = {Ya. B. Zel’dovich},
	title = {Interaction of free electrons with electromagnetic radiation},
	publisher = {Physics-Uspekhi},
	year = {1975},
	journal = {Phys. Usp.},
	volume = {18},
	number = {2},
	pages = {79-98},
	url = {https://ufn.ru/en/articles/1975/2/a/},
	doi = {10.1070/PU1975v018n02ABEH001947}
}