Illumination asymmetries in laser-induced compression

Henderson and Morse (1974) treated the symmetrizing effect of thermal conductivity in laser-induced compression, indicating that the high conductivity of the plasma surrounding an ablating sphere can smooth out asymmetries in illumination intensity and result in a uniform heat flow to the ablating surface thus giving a symmetric implosion. The paper derives two conditions which indicate when symmetric energy flow to the ablating surface can be expected. The first condition is that the time for a thermal wave to travel from the critical radius to the ablation radius is greater than the time for the wave to propagate azimuthally and coalesce, and the second condition is that the thermal waves in the corona must always be supersonic.