We calculate rates of transitions between proton Landau levels due to non-radiative and radiative Coulomb collisions in an electron-proton plasma with strong magnetic field B and solve the balance equation for populations of proton Landau levels. For temperatures of the order of 10⁶-10⁷ K, the deviations from LTE are appreciable at density below (0.1 B₁₄³) g cm^-3, where B₁₄=B/10¹⁴ G. We calculate the emissivity of the plasma and demonstrate that it is close to the LTE emissivity even in the case where the level populations deviate from LTE by orders of magnitude.

Generalization for ions other than protons is straightforward.

Page created on September 7, 2006.