Studies on Coaxial Plasma Discharge

Abstract

This thesis includes three parts: the first part involving design, fabrication and construction of a 2.5 kJ coaxial plasma discharge device, the second part involving the electrical parameters and efficiency of 2.5 kJ coaxial plasma discharge device, the third part involving plasma current sheath dynamical behavior along the coaxial electrodes system A coaxial plasma discharge device used in this experiment has the following parts :The discharge chamber consists of two stainless steel coaxial electrodes separated by an insulator perspex cylinder of 1.5 cm length at one end, where the breakdown of the gas discharge takes place. The negative inner electrode is made of 16.5 cm length cylinder of diameters of 3.18 cm. The Positive outer electrode is made of 35 cm length cylinder of minor diameters of 15.7 cm. The coaxial plasma discharge device is powered by a capacitor bank of . The filled gas is helium gas of pressure in the range from 0.81 to 3.2 Torr and charging voltage of 10 kV. Many diagnostic techniques are used in this work, including a Rogovsky coil, miniature Rogovsky coil, magnetic probe and voltage divider to measure the discharge current, the radial plasma current sheath density, the magnetic field induction in axial and azimuthal directions along the coaxial electrodes, and the voltage between the coaxial electrodes during the discharge process. Results of the discharge current measurements and the voltage between the coaxial electrodes during the discharge process showed that the maximum discharge current value = 103.64 kA and 83.14 kA at P = 1.6 Torr and P = 3.2 Torr during the first and second half cycles of discharge respectively and the maximum voltage during the first and second half cycles = 2.89 kV at P = 3.2 Torr and 1.85 kV at P= 2 Torr respectively.