TEMPERATURE OF A LASER-HEATED CARBON PLASMA

The temperature of a laser-heated carbon plasma, formed by the interaction between a Q-switched ruby laser and a pyrolytic graphite slab, has been measured using interferometric, spectroscopic, and energy conservation techniques. Results indicate that the maximum plasma temperature is less than 10 eV. A method of determining whether the plasma is in thermodynamic equilibrium is employed and indicates that at laser fluxes of 109 W/cm2 the plasma is not in LTE with the electron temperature nearly an order-of-magnitude larger than the plasma temperature. For fluxes of 10 10 W/cm2, however, the plasma appears to approach a state of thermodynamic equilibrium with a temperature of 2eV. © 1969 The American Institute of Physics.