Collective effects of plasma particles in bremsstrahlung

In the classical limit, bremsstrahlung corresponds to scattering of virtual fields of the colliding electron and ion on the incident electron. This statement is no longer correct in the case when the collective effects in bremsstrahlung are taken into acount. These effects can change drastically the cross-sections of bremsstrahlung because of the important role of scattering of virtual waves on the Debye shielding shells of colliding particles. In particular, the scattering on ions (their Debye shielding clouds) is important (while in the absence of collective effects the scattering on a single ion is negligible). In this article it is shown how the present theory of fluctuations in a plasma, with the nonlinear fluctuations taken into acount, leeds to the determination of cross-sections of bremsstrahlung, which take into acount all collective effects that are important for this process.