Simulating the heating of z-pinch plasmas with short laser pulses

The longitudinal heating of a z-pinch plasma with short laser pulses is simulated using COMSOL Multiphysics. The heating of an existing pinch plasma for different electron densities with a short laser pulse is shown. It is illustrated that the initial electron density of the plasma has a significant impact on penetration of the pulse and subsequent heating of the plasma. With a Nd:YAG laser pulse the most effective heating occurs when the initial electron density is about 1/15 of the critical electron density of the plasma. It is shown that by increasing the initial electron density by even a factor of two above this level causes the absorption to increase dramatically, preventing penetration of the laser pulse and greatly limiting the heating of the plasma.

Skin-depth effect of a cylindrical shock-produced plasma

The microwave reflexion from and transmission around the shock-produced argon plasma whose electron density is greater than 102 times the critical electron density for the 9 Gc/s wave have been found to be similar to those of a metal rod. But the skin depth of the wave in the plasma plus the thickness of the shock boundary layer is found to affect significantly the amount of microwave power transmitted round the cylindrical surface of the plasma.