核聚变ECRH系统用连续波回旋振荡管模式竞争与稳定性研究

Energy shortage and environmental problems are the two largest challenges for human beings now. Magnetic confinement nuclear fusion , which has achieved great progress since the 1990's , is anticipated to be a significant way to realize an ideal source of energy in the future because of its abundance , environmental compatibility , and zero carbon release. MW output power CW gyrotron oscillators (gyromonotrons) are mainly used as high power millimeter wave sources for electron cyclotron resonance heating (ECRH), electron cyclotron current drive (ECCD), stability control and diagnostics of magnetically confined plasmas for generation of energy by controlled thermonuclear fusion. The major advanced countries make a point of developing MW output power CW gyrotrons, so these devices have been well studied recent years in those countries. But this work has not been done in our country yet. This project will study on the key techniques of 140 GHz MW output power CW gyrotrons, especially focusing on probing into characteristics of new RF structure and discovering new interaction mechanisms which operate well in highly overmoded circuits and reduce the problem of mode competition, which means in fast wave circuits where the e-beam is placed well away from the RF structure and continuous stable MW output power in the millimeter- and submillimeter-wavelength range can be achieved. By linear and self-consistent nonlinear theory analysis, physical model approximations of the beam-wave interaction process in RF structure and analyzing the influence of all work parameters and thermal effect, we will deeply study on beam-wave highly efficient interaction mechanisms of the specific components in modern high-power fusion gyrotrons, the effective way to suppress parasite oscillations and mode competitions between high order modes and the feasible method of achieving continuous stable MW output power through calculating, simulating, analyzing and doing experiment.

能源短缺和环境恶化是人类社会面临的两大挑战。由于资源丰富、环境友好和零碳排放,核聚变能是未来的理想能源，并自上世纪90 年代以来取得了重大研究进展。作为磁约束核聚变中电子回旋共振加热、电流驱动、稳定性控制和诊断的理想手段，兆瓦级连续波回旋振荡管研究工作在国际上受到高度重视并在世界主要发达国家进行了深入研究，而我国在该领域回旋管的研究还尚属空白。本项目将开展核聚变用140GHz回旋管关键技术研究，重点探索新型高频结构及深入研究过模腔体中高阶腔体模工作的注波互作用机理，寻找抑制寄生振荡与模式竞争的有效方法，解决大功率回旋管连续稳定工作问题。通过线性理论与自洽非线性理论分析;建立高频互作用系统物理模型，对注波互作用过程、模式竞争、热效应及各工作参数影响计算、仿真、实验与分析，对大功率回旋管新型注波互作用系统高效换能机制、抑制模式竞争有效手段及维持大功率连续波回旋管稳定工作的方法进行深入分析研究。

作为等离子体设备所需要的重要工具，回旋振荡管已被证明是110GHz到170GHz频段上的高效相干毫米波辐射源，并且已经成功用于电子回旋共振加热（ECRH）和电子回旋波电流驱动实验中。本项目开展了核聚变用兆瓦级回旋管关键技术研究的工作，重点探索了新型高频结构及深入研究过模腔体中高阶腔体模工作的注波互作用机理，寻找抑制寄生振荡与模式竞争的有效方法，解决大功率回旋管连续稳定工作问题。通过线性理论与自洽非线性理论分析;建立了高频互作用系统物理模型，对注波互作用过程、模式竞争、热效应及各工作参数影响进行了大量计算、仿真实验与分析，对大功率回旋管新型注波互作用系统高效换能机制、抑制模式竞争有效手段及维持大功率连续波回旋管稳定工作的方法进行了深入分析研究。. 通过对140GHz高功率聚变用回旋管注-波互作用高频系统进行的研究， 我们优化设计出了更加合理的结构与尺寸， 当工作电压75kV,电流45A时，互作用效率达到35.3%,其输出功率约为1.1MW；对连续波工作时电子注-波互作用过程中谐振腔体壁损耗引起的热变形与散热问题进行分析研究，当满功率输出1.1MW时，最大壁损耗功率密度0.97 kW/cm2，腔体壁损耗共计20.9 kW，为满足ECRH 系统用MW级连续波回旋管长时间稳定工作要求和下一步开展整管的设计与实验工作奠定了重要基础。