Impact of hydrogen isotope species on microinstabilities in helical plasmas
Impact of hydrogen isotope species on microinstabilities in helical plasmas
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DOI：
10.1088/0741-3335/58/7/074008
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发表时间：
2016-06
影响因子：
2.2
通讯作者：
M. Nakata;M. Nunami;H. Sugama;Tomo-Hiko Watanabe
中科院分区：
文献类型：
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作者：
M. Nakata;M. Nunami;H. Sugama;Tomo-Hiko Watanabe
采用氢同位素和实质量动力学电子的回旋动力学Vlasov模拟，研究了同位素离子质量对螺旋等离子体中离子温度梯度（ITG）模式、俘获电子模式（TEM）和电子温度梯度（ETG）模式等离子尺度和电子尺度微观不稳定性的影响。全面扫描的平衡参数和磁配置澄清从ITG模式的TEM不稳定性，其中一个显着的TEM增强的情况下，揭示了向内移动的等离子体相比，在标准配置的过渡。阐明了离子质量对电子-离子碰撞频率与离子渡越频率之比的依赖性，即νei/ωti（mi/me）1/2，导致较重同位素离子的TEM稳定。ITG增长率表明类似于陀螺玻姆的离子质量依赖性，其中扩散率的混合长度估计产生γ/k 2 mi 1/2。另一方面，确定了ETG生长速率的弱同位素依赖性。碰撞性扫描还表明，TEM稳定的同位素离子变得更显着的香蕉政权相对较高的碰撞。
The impact of isotope ion mass on ion-scale and electron-scale microinstabilities such as ion temperature gradient (ITG) mode, trapped electron mode (TEM), and electron temperature gradient (ETG) mode in helical plasmas are investigated by using gyrokinetic Vlasov simulations with a hydrogen isotope and real-mass kinetic electrons. Comprehensive scans for the equilibrium parameters and magnetic configurations clarify the transition from ITG mode to TEM instability, where a significant TEM enhancement is revealed in the case of inward-shifted plasma compared to that in the standard configuration. It is elucidated that the ion-mass dependence on the ratio of the electron–ion collision frequency to the ion transit one, i.e. νei/ωti∝(mi/me)1/2, leads to a stabilization of the TEM for heavier isotope ions. The ITG growth rate indicates a gyro-Bohm-like ion-mass dependence, where the mixing-length estimate of diffusivity yields γ/k⊥2∝mi1/2. On the other hand, a weak isotope dependence of the ETG growth rate is identified. A collisionality scan also reveals that the TEM stabilization by the isotope ions becomes more significant for relatively higher collisionality in a banana regime.