ANALYSIS OF THE IMPEDANCE OF A COAXIAL, LARGE-BORE COPPER-VAPOR LASER

The impedance of the laser head of a 100-W copper-vapor laser is inves tigated. The laser head is of a coaxial geometry, which is commonly us ed for longitudinally electrically excited, pulsed-gas lasers. The pla sma conductivity is estimated using the available data on plasma param eters. The effect of radial gradient of the gas temperature and electr on density is considered. The tube inductance and capacitance are esti mated and the combined effect is demonstrated. The skin effect is cons idered. A method to calculate the exact influence of the skin effect o n the tube impedance is presented. The full calculation procedure is d emonstrated for the case of a 100-W, 8-cm-diameter, copper-vapor laser . The consequent impedance is used to calculate the laser current unde r given excitation conditions. Very good agreement exists between the calculated and measured laser current. The metal-sleeve diameter is fo und that is optimal for power matching.