Probe diagnostics of abnormal glow discharge in pure conditions

The work is devoted to the study of a direct current abnormal glow discharge in helium with a copper cathode under “physically pure” conditions. In pressure range 3.5-9 Torr of helium, the nonmonotonic current-voltage characteristics of a discharge with a cold copper cathode were demonstrated. The study of the distribution of the electric field in the region of the cathode sheath and the calculated dependences of the effective Townsend electron multiplication coefficient demonstrated the correlation of the latter with the current-voltage characteristics and a change in the discharge mechanism when the minimum current is reached at a voltage of ~ 1500 V for the conditions of this work.