Paper Title
Effect of Hollow Anode Depthon some Characteristics and Parameters of Argon Glow Discharge Plasma

An experimental investigation of hollow anode argon glow discharge plasma has been carried out at different argon gas pressure ranged from 2.2×〖10〗^(-2) to 3mbar forconstant discharge current. The glow discharge usually obtained by applying a high voltage between the electrodes sufficient to occurring breakdown of argon gas and sustaining the discharge. The experiments were conducted firstly to measure the breakdown voltage and Paschenc's law under the influence of hollow anode depth. A constant cathode disc of radius 20mm as well as hollow anodes of constant inner diameter 20mm and depths of values (10, 15, 20, 25, 30, 35, and 40) mm have been taken into consideration. Secondly, the study has been extended to measure some plasma parameters in the negative glow region of direct current argon glow discharge under the same conditions. Electric probes and a computer MATLAB program are used to obtain the temperature and density of electrons in the negative glow region from the double probes (Ip-Vp) characteristic. It was found from the results that the measured Pashence's curve closes to the well-known theoretical Pashence's law. The voltage breakdown and its minimum breakdown voltage decrease due to increasing the depthof cylindrical hollow. Increasing the hollow anode depth, the Paschen’s curve is widening. A dens and luminous intensity of plasma occurs in the negative glow region due to reduction of hollow anode depth. Both electron temperature and density of electron are decreases due to increasing the depth. Keywords - Hollowanode Depth, Argon Glow Discharge, Double Probes Plasmaparameters, Negative glow Region, Matlabprogram.