Thermal recovery optimization method of high-power laser driver based on multi-slab gas-cooled configuration

One of the key factors of limiting the application of laser fusion energy is the long heat recovery time of existing high-power laser drivers, and more effective thermal management methods can quicken the thermal recovery of high-power laser driver. A new main amplifier design was proposed based on the multi-slab gas-cooled design for the four-pass amplification in ShenGuang Ⅱ upgrade device (SG-II-UP). The numerical simulation about thermal recovery of the new design was conducted through the finite element analysis software. The results show that the recovery time of temperature gradient is about 37 minutes and the recovery time of wavefront is about 23 minutes, which are 22.6% and 19.0% of the existing structure, respectively. The new design added gaps between slabs for nitrogen cooling which leads to the increase the need of nitrogen. However, the summation of nitrogen required for cooling the Nd:glass in a single shot is 45% of the existing structure, due to the shortened heat recovery time. The results show that the new design is capable of reducing thermal recovery time effectively and provide basis and references for the optimization of shenGuang Ⅱ upgrade device (SG-II-UP).