On the radial distribution and nonambipolarity of charged particle fluxes in a nonmagnetized planar inductively coupled plasma

The radial distribution of electron and ion fluxes to conducting and nonconducting walls in a planar inductively coupled plasma has been studied experimentally and theoretically. Measurements of electron and ion currents have been performed using electrostatic probe arrays. Radially resolved measurements of ion impact energies have been performed using an ion energy analyzer array. For conducting walls it is shown by calculations and measurements that electron and ion currents are not in balance locally but that diffusion is nonambipolar. The ion impact energies measured on a conducting surface show a significant radial variation in accord with our theoretical model. For nonconducting surfaces the ambipolar fluxes of electrons and ions result in the formation of a surface charge potential profile across the surface. Voltages of the order of several volts between the center and the periphery of the surface are measured.