Progress and issues in understanding the physics of ELM dynamics, ELM mitigation, and ELM control
Progress and issues in understanding the physics of ELM dynamics, ELM mitigation, and ELM control
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DOI：
10.1088/1742-6596/123/1/012002
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发表时间：
2008-07
期刊：
影响因子：
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通讯作者：
N. Oyama
中科院分区：
文献类型：
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作者：
N. Oyama
综述了在理解第一类ELM的动力学、实现ELM缓解和主动ELM控制的小/无ELM制度方面的最新实验进展。对于第一类ELM动力学，ELM先驱相对于Alfven频率的生长速率较小，ELM细丝对评估ELM热负荷的重要性，恢复阶段基座压力的演变，以及边缘环旋转和环向场波动对ELM能量损失的影响，在许多器件中都观察到了。在低碰撞性(ve*)小/无Elm区，在ve*<；1条件下获得了单丝或双丝的V型ELM。在非旋转等离子体中的草状榆树区域，获得了小于1%的归一化榆树能量损失。在QH模式下，当边缘环向旋转与等离子体电流相反时，基座压力达到最高。论证了弹丸起搏和外加磁场扰动对ELM的控制/抑制，从而启动了ITER ELM控制线圈的设计活动。研究发现，边缘环旋转对Elm特性有多种影响，如I型Elm区和草状Elm区的Elm能量损失(Elm频率)，QH模区的边缘简谐振荡和可实现的基座压力的变化，以及Elm控制线圈在岛屿形成评估中的屏蔽效应。
Recent experimental progress in understanding the dynamics of type I ELM, small/no ELM regimes to achieve ELM mitigation and active ELM controls is reviewed. As for the type I ELM dynamics, the smaller growth rate of the ELM precursor relative to the Alfven frequency, the importance of ELM filaments to evaluate the ELM heat load, the evolution of pedestal pressure in the recovery phase, and the effects of edge toroidal rotation and toroidal field ripple on ELM energy loss have been observed in many devices. In low collisionality (ve*) small/no ELM regimes, the type V ELM has been obtained with one or two filaments in ve*<1 condition. Small normalized ELM energy loss less than 1% has been achieved in the grassy ELM regime in non-rotating plasmas. The highest pedestal pressure has been achieved with smaller edge toroidal rotation counter to the plasma current in the QH-mode. ELM control/suppression by pellet pacing and external magnetic field perturbation has been demonstrated, and so that a design activity of ELM control coils for ITER has started. Various effects of the edge toroidal rotation upon ELM characteristics have been found such as ELM energy loss (ELM frequency) in the type I ELM regime and the grassy ELM regime, changes in edge harmonic oscillation and achievable pedestal pressure in the QH-mode regime, and a screening effect in evaluation of island formation by ELM control coils.