Confinement and gas fueling in LHD limiter discharges
Confinement and gas fueling in LHD limiter discharges
复制标题
LHD 限制器排放中的限制和气体燃料
DOI：
10.1016/s0022-3115(02)01394-6
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发表时间：
2003
影响因子：
3.1
通讯作者：
Kenji Tanaka
中科院分区：
文献类型：
--
作者：
K. Nishimura;K. Kawahata;K. Narihara;T. Morisaki;S. Masuzaki;S. Sakakibara;Kenji Tanaka
大螺旋装置中的等离子体放电是常开螺旋偏滤器放电。为了比较限制器放电与开放偏滤器放电，并检查周边区域的作用，径向可移动的限制器，其头部是由具有高导热性的碳制成，从高场侧（靠近螺旋线圈）插入到等离子体中。电子温度受限制器的约束。在偏滤器和限流器的开放放电中，都观察到了边缘区域的高温度梯度。即使在限制器放电中，如此高的温度梯度的形成也导致良好的能量约束，并且在每个限制器位置（0.75<ρ<1）处观察到国际仿星器标度95（ISS 95）标度的增强因子为1.1±0.3。在限制器放电中没有观察到通过增加再循环和/或杂质而导致的等离子体约束的严重退化。在这些实验条件下，等离子体小半径对能量约束时间的依赖关系与ISS 95标度律相同。Rax=3.75 m的厚各态历经层可防止气体通过喷吹加注燃料。
Plasma discharges in the Large Helical Device are normally open helical divertor discharges. To compare limiter discharges with open divertor discharges and to examine the role of the peripheral region, a radial movable limiter, whose head was made of carbon with high heat conductivity, was inserted into the plasma from the high field side (near the helical coil). The electron temperature was bounded well by the limiter. A high temperature gradient at the edge region was observed in both open divertor and limiter discharges. Formation of such a high temperature gradient led to good energy confinement even in the limiter discharges and an enhancement factor of 1.1±0.3 for International Stellarator Scaling 95 (ISS95) scaling was observed at every limiter position (0.75<ρ<1). Serious degradation of the plasma confinement by increase of recycling and/or impurities was not observed in the limiter discharges. Within these experimental conditions, the dependence of the plasma minor radius on the energy confinement time was same as that of the ISS95 scaling law. A thick ergodic layer with Rax=3.75 m prevents gas fueling by puffing.