On integral absorption coefficient of electromagnetic waves beam on the critical surface of radially nonuniform plasma ball

A simple analytical formula for integral coefficient of resonance absorption of electromagnetic waves beam on a spherical critical surface of plasma ball was derived. The boundaries of applicability of the plane critical surface approximation for the calculation of resonance absorption have been ascertained. The influence of the beam aberrations and shift (including occasional one) of the beam axis from the ball centre on resonance absorption has been analyzed. 14 refs.; 7 figs