Dynamics of weak-magnetic-shear-sustained internal transport barrier during supersonic molecular-beam injection in JT-60U
Dynamics of weak-magnetic-shear-sustained internal transport barrier during supersonic molecular-beam injection in JT-60U
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DOI：
10.1088/1741-4326/abcad3
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发表时间：
2021-02-01
期刊：
影响因子：
3.3
通讯作者：
Isayama, A.
中科院分区：
文献类型：
--
作者：
Kin, F.;Yoshida, M.;Isayama, A.
利用超声分子束注入（SMBI）产生的冷脉冲，研究了JT-60 U中弱磁剪切下离子在内输运势垒（ITB）中的热输运特性。众所周知，ITB中的冷脉冲传播通常会显著降低温度并降低温度梯度。当在温度恢复之前启动后续SMBI时，观察到ITB的温度梯度不是单调降低，而是交替降低和增加。ITB温度梯度的交替下降和上升阶段持续约1 s（类似于6 τ（E）），并且冷脉冲传播的性质和通量梯度关系根据阶段而不同。通常的瞬态输运分析也提供了诱导一个冷脉冲在静止ITBs。一个快速的降低和恢复的温度内观察到的ITBs，它被发现，离子热通量的变化没有变化的本地离子温度梯度或其他可观察到的本地参数的变化。磁通梯度关系表现出显着的滞后在两个ITB的情况下：（i）ITBs与强电子密度梯度和（ii）ITBs与弱离子温度梯度。此外，滞后出现的范围最可能取决于ITB的宽度。
The characteristics of ion heat transport inside the internal transport barrier (ITB), which is sustained by weak magnetic shear, are investigated using a cold pulse induced by supersonic molecular-beam injection (SMBI) in JT-60U. It is known that cold-pulse propagation in ITBs usually significantly reduces the temperature and degrades the temperature gradient. When subsequent SMBIs are launched before the temperature has recovered, it is observed that the temperature gradient of the ITB is not monotonically decreased but alternately decreased and increased. Alternating decreasing and increasing phases of the ITB temperature gradient continue for about 1 s (similar to 6 tau(E)), and the properties of the cold-pulse propagation and the flux-gradient relations differ according to the phase. The usual transient transport analysis is also provided by inducing a cold pulse in stationary ITBs. A rapid reduction and recovery of the temperature is observed inside the ITBs, and it is found that the ion-heat flux changes without a variation in the local ion-temperature gradient or a change to the other observable local parameters. The flux-gradient relations exhibit significant hysteresis in two ITB cases: (i) ITBs with strong electron-density gradients and (ii) ITBs with weak ion-temperature gradients. In addition, the range in which hysteresis appears is most likely to depend on the width of the ITB.