Electron Heating and Current Drive by Electron Bernstein Waqves

普通（O-）和特殊（X-）模式等电磁波通常用于电子回旋共振加热（ECRH），其具有密度限制，称为截止密度。因此，这些模式在高密度状态下是无用的。需要开发另一种加热方案来生产和加热高密度等离子体，而不考虑截止密度。电子伯恩斯坦波（EBW）是一种静电波，其优点是没有截止密度，即使在10 eV的低电子密度下也有很高的吸收效率。在本研究中，为了研究EBW加热，开发了计算环形结构吸收效率的射线追踪代码。计算结果表明，功率吸收谱对电子密度和温度等等离子体参数的敏感性较弱，这有利于实验证明O-X-B加热。在更多的螺旋系统中，由于其磁场结构，可以通过从低场侧端口斜向环形方向发射光束来实现缓慢的X-B模式加热。在球形环面中，由于传统的ECRH具有较高的等离子体介电性能，难以使用，因此在电子加热和电流驱动方面具有重要作用。与螺旋系统类似，数值证明了O-X-B加热是可能的，并且得到了对等离子体参数和磁场的依赖关系。在等离子体实验中，在Heliotron J和LHD器件中实验观察到X-B模式转换加热。在Heliotron J中，即使在核心等离子体区域不存在电磁共振的情况下，其存储能量也达到了与二次谐波x模ECRH相当的1 kJ。这可以用缓慢的X-B模式转换加热来解释。在LHD中，一些实验结果表明，当光束在环形方向上斜发射时，X-B模式转换加热。根据FFT分析，功率吸收曲线在ECR层低场侧的局部区域达到峰值。少

The electromagnetic waves such as the ordinary (O-) and extraordinary (X-) modes are conventionally used for electron cyclotron resonance heating(ECRH), which has a density limit so called cutoff density. Therefore these modes are not useful at high density regime. It is desirable that another heating scheme should be developed for the production and heating of high density plasma regardless of cut off density. The electron Bernstein waves(EBW) is a electrostatic wave which has advantages that there is no cutoff density and that the absorption efficiency is quite high even at low electron density of a few 10 eV.In this research, ray tracing codes to calculate the absorption efficiency have been developed for toroidal configurations in order to study the EBW heating. The calculation results indicate that the power absorption profile is weakly sensitive to plasma parameters such as electron density and temperature, which is favorable for experimentally demonstrating the O-X-B heating. In … More helical systems, the slow X-B mode heating is possible by launching the beam obliquely in the toroidal direction from low field side port due to its magnetic field structure. In spherical torus, the EBW has an important role on the electron heating and current drive, since it is difficult to use the conventional ECRH owing to high plasma dielectric properties. Similarly as helical systems, it is numerically demonstrated that the O-X-B heating is possible, and the dependence on the plasma parameters and magnetic field is obtained.In plasma experiments, the X-B mode conversion heating has been experimentally observed in the Heliotron J and LHD devices. In Heliotron J, the stored energy reaches 1 kJ comparable to the second harmonic X-mode ECRH even when the electromagnetic resonance does not exist in the core plasma region. This can be explained by the slow X-B mode conversion heating. In LHD, some experimental results implying the X-B mode conversion heating has be obtained when the beam is launched obliquely in the toroidal direction. According to the FFT analysis, the power absorption profile is peaked in a localized area of the low field side from ECR layer. Less