Experimental study of transformer-coupled toroidal discharge in mercury vapour

Abstract

Experimental investigations of the transformer-coupled toroidal discharge (TCTD) in a mixture of argon and mercury vapour were carried out for a wide range of discharge parameters: mercury vapour pressure (0.1–40 000 Pa), discharge current (1–260 A), diameter of a gas-discharge tube (20–75 mm) and current frequency (10–250 kHz). New experimental data on electric field strength and emission yield to visible and UV-range were obtained as functions of the discharge parameters. It was proved that the dependences of electrical and optical characteristics of TCTD on the discharge current, vapour pressure and tube diameter are close to those of dc arc discharges in mercury vapour. The possible reasons for parameter deviations were considered. Also, the effect of the reduction of emissivity for the visible triplet of mercury spectrum (404.7, 435.8, 546.1 nm) with the excitation potential of 7.73 eV was discovered under certain conditions: mercury vapour pressure is higher than 10 kPa, and the specific power is above 50 W cm−1.