低杂波和离子回旋波协同效应对参量衰变不稳定性的影响

射频波已成为磁约束聚变等离子体加热，电流驱动以及等离子体控制的一种重要手段。随着聚变装置中射频波入射功率的增加，理论和实验都发现，射频波参量衰变不稳定性（PDI）将严重影响波的传播和能量沉积。但现有的理论模型只研究了单波作用下的PDI过程，双波协同作用对PDI的影响没有考虑。本项目将从解析理论和数值模拟两个方面对离子回旋波和低杂波共同作用下的射频波参量衰变过程进行研究。首先从动理学理论出发，推导低杂波和离子回旋波共同作用下参量衰变不稳定性的非线性色散关系；然后分析双波协同效应对参量过程的影响。最后通过粒子模拟程序，验证解析理论结果，并更自洽地研究双波协同作用对参量不稳定的影响。

Radio frequency (rf) waves have been widely used for plasma heating, current drive and control. As the input power of rf waves increases, it is found theoretically as well as experimentally that the parametric decay instability (PDI) can significantly affect the wave propagation and energy deposition. The existing theories, however, are developed only for PDIs produced by a single pump wave. The synergetic effects of rf waves on PDIs have never been studied. In this proposed project, the PDIs during combined application of a lower hybrid wave and an ion cyclotron wave will be studied. The nonlinear dispersion relation of the PDI will be obtained based on kinetic theory, and the effects of the synergy between the two types of waves on the PDI will be investigated. The particle-in-cell simulations will be carried out to study the PDI and the theoretical and simulation results will be compared.