  By applying a method of virtual quanta we derive formulae for relativistic
non-thermal bremsstrahlung radiation from relativistic electrons as well as
from protons and heavier particles with power-law momentum distribution $N(p)dp
= k p^{-q} dp.$ We show that emission which originates from an electron
scattering on an ion, represents the most significant component of relativistic
non-thermal bremsstrahlung. Radiation from an ion scattering on electron, known
as inverse bremsstrahlung, is shown to be negligible in overall non-thermal
bremsstrahlung emission. These results arise from theory refinement, where we
introduce the dependence of relativistic kinetic energy of an incident
particle, upon the energy of scattered photon. In part, it is also a
consequence of a different mass of particles and relativistic effects.
