给出了神光Ⅲ原型装置主放大器系统的热畸变模型，该模型包括三个模块:热传输模块、热弹性力学模块、光学模块。利用该模型对原型装置的剩余热波前畸变进行了研究。初步结果表明，通过优化的冷却方案，可以在装置预定的运行周期内将激光工作介质内的温度梯度和总体平均温度冷却到可以接受的水平，剩余热波前畸变满足设计要求。利用该模型还定量地研究了增益介质的热膨胀系数与剩余热畸变之间的关系。

A thermo-elasto-opticaldistortion model for the main amplifier of SG-Ⅲ prototype is presented in this paper, which consists ofthree modules, i.e., modules of heat transfer, thermo-elastics and optics. With thismodel, the residual thermal distortion of the main amplifier of SG-Ⅲprototype is investigated. The calculatingresults indicate that, with an optimization thermal recovery, the thermal gradient and theaverage temperature of the slab can be reduced to an acceptable value. The residualthermo-optical distortions can meet the design requirements. Additionally, a quantitativerelation between the thermal distortion and the linear thermal expansion coefficient ofthe laser gain medium have been also obtained.