The time evolution of the electric characteristics of a laser discharge through their waveforms of the voltage and the current

Abstract

The time behavior of the electric characteristics resistances and inductances in the discharges in pulsed gas lasers is revealed through a procedure which exploits only the voltages or the currents waveforms. This can be achieved combining step by step the waveforms with the equations governing the performance of the system. This method is described analytically in the text. Its application showed that the resistances drop rapidly (first l0nsec) from very high values to low values, while the inductances increase to high values and subsequently decrease, forming an abrupt high peak (first 40nsec). The steep drop of the resistances is due to the electron avalanche multiplication, while the peak of the inductances is due to the centripetal magnetic forces (Laplace forces), which cause a temporary constriction of the plasma. In the “main phase” of the discharge the resistances present a damping oscillation with the same frequency as the voltages, while the inductances present light fluctuations around constant values. The time varied resistances and inductances strongly influence the electrical and optical behavior of the laser system.