Violation of the Boltzmann distribution for plasma electron number density in two-chamber inductively coupled plasma discharges

It is found for inductively coupled plasma (ICP) discharges in two-chamber structures in which a strong electron temperature gradient can be produced, the classical Boltzmann distribution for the electron number density does not exist even at qualitative level; a more general (extended Boltzmann) distribution for the electron energy density holds with a satisfactory accuracy.