Polarization bremsstrahlung of a fast charged particle on a Thomas-Fermi atom

An universal description of the polarization bremsstrahlung of a fast charged particle on a multielectron atom (Z much greater than 1, Z is the nuclear charge) is obtained using the local electron density method and the Thomas-Fermi statistical model. It is shown that the cross section of the process can be represented in the form d sigma(PB)(omega) = Z(2)d<(sigma)over tilde>(PB)(nu), where the function d<(sigma)over tilde>(PB)(nu) exhibits approximate scaling with respect to the parameter omega/Z = nu, and the corresponding R factor (ratio of the cross sections in the polarization and ordinary channels) is greater than 1 in a wide range of frequencies and reaches its maximum value at frequencies omega approximate to Z Ry. It is demonstrated that in the frequency range p(a)c < (h) over bar omega < gamma(2)p(a)c (gamma is the relativistic factor, p(a) is the characteristic momentum of the atomic electrons, and c is the speed of light) the angular distribution of the polarization bremsstrahlung of a relativistic charged particle undergoes narrowing due to the compensation, by the momentum of the emitted photon, of the momentum transfer from the incident particle to the atomic core. (C) 2000 MAIK "Nauka/Interperiodica".