Critical surface bubbles and corrugations and their implications to laser fusion Available to Purchase

Bubbles are concentrations of electromagnetic energy in the region of the critical density that force the plasma out to form a cavity. Since the critical density surface becomes cratered, absorption may be greater than for a smooth surface. A larger area is available for absorption and the reflected light has a large probability of restriking the critical density. The distance between bubbles is several wavelengths and consequently, they may encourage Rayleigh–Taylor instabilities. Two different kinds of two‐dimensional simulation models are used to study the cases of light polarization in and out of the plane of incidence. With the electric field in the simulation plane, corrugations appear in the critical surface. Resonant absorption can occur on these angular surfaces even with the pump light perpendicularly incident. Since the problem is inherently three‐dimensional and kinetic, the limitations of the models are described. The threshold, magnetic field generation, and possible experimental evidence for bubbles are discussed. Also, the competition between sidescatter and self− focusing in an entirely underdense plasma is studied, and it is found that sidescatter dominates for polarization out of the simulation plane.