Characteristics of the electrode plasma of an electrode microwave discharge in hydrogen

The electrode region of an electrode microwave discharge in hydrogen at pre ssures of 0.5-4 torr and absorbed powers of up to 12 W is studied using emi ssion spectroscopy and actinometry. It is shown that the gas temperature is at most 700 K and the degree of dissociation does not exceed several perce nt. Direct electron impact is shown to be the main factor governing all the processes in the electrode region of the discharge, including the excitati on of the recorded emission. In particular, the Balmer-series H-alpha line emission is related to the dissociative electron-impact excitation of hydro gen molecules in the ground state. (C) 2001 MAIK "Nauka/lnrerperiodica".