Fusion Science and Technology / Volume 49 / Number 4 / May 2006 / Pages 574-580
Technical Paper / Target Fabrication
This paper is an update of the thermal and hydrodynamic simulations of cryogenic target for the laser MegaJoule (LMJ). Depending on the kind of study, 2-D axi-symmetric or 3-D models are used for those numerical simulations with FLUENT, a Computational Fluid Dynamics (CFD) code.
Results show the response of the hohlraum assembly and the DT ice layer profile to sinusoidal modulation of the temperature of the cooling rings. aWe have also calculated that no change in the DT ice was observed with variations up to +/-2 mK on thermal shroud. Results of flux absorption during laser alignment are reported here.
Taking in account the cavity real geometric configuration, the seven gas-areas cavity appears to be the most effective to counteract convection effects. Other ways to counteract those effects have been explored like heating modulation in the central area on the outer surface of the gold cavity, or uniform heating in this area with auxiliary heating on the lower cooling ring. More, the thermal response of DT ice when it is submitted to a quenching (in order to obtain the LMJ target gas density specification) is shown here.