The Non-Maxwellian Distribution in a Shock Front and the Anomaly of the Chromospheric Temperature

Abstract

An estimate is made of the departure from the Maxwellian distribution of the particle velocities in a shock front, as a function of the shock strength. Expressions are derived for the absorption and emission coefficients (for electronic free-free transitions in a completely ionized gas) in a shock front of given strength. The results obtained are applied to resolve the apparent conflict between the two electronic temperatures of the chromosphere, as indicated by optical (30 000°K from emission line widths) and radio (10 000°K from centimetric radiation intensity) observations of the sun.