Temperature Control in a Cryogenic Target with a Conical Laser Guide for Fuel Layering

Abstract

Fuel layering of a cryogenic target with a conical laser guide such as the FIREX target is complicated because of its non-spherical symmetry appearance. To simplify the layering, a foam layer is planned to utilize as a supporting material of fuel. Ideally, the foam shell has self-fuel-layering ability at a liquid state owing to the capillarity of the foam material. For stable fuel compression in laser experiments, the fuel must be solid with a lower saturated pressure. The transition to a solid state expects to cause random fuel crystallization and voids from the density difference between liquid and solid. A volumetric heat load might help to finish fuel layering even in the foam shell. Solid fuel redistribution will ignore the foam boundary. Temperature control in the target, therefore, is required during the formation of a uniform layer. For the rough estimation of the target temperature, the possibility of the ANSYS code was confirmed compared with the experiment using a dummy target. Then, steady state temperature profiles of the FIREX target were calculated using the ANSYS code. Temperature control to practically realize a uniform solid fuel layer in the FIREX target is discussed.