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 1s (∼6τ _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.

利用超音速分子束注入（SMBI）在JT-60U中产生的冷脉冲，研究了内部传输壁垒（ITB）内部的离子传热特性，该特性通过弱磁剪切而得以维持。众所周知，ITB中的冷脉冲传播通常会显着降低温度并降低温度梯度。当随后的SMBI在温度恢复之前启动时，可以观察到ITB的温度梯度并不是单调降低，而是交替降低和升高。交替的减小和增加的ITB温度梯度的相持续约1秒（〜6 τ _Ë），冷脉冲传播的特性和磁通量梯度关系根据相位而有所不同。还可以通过在固定ITB中产生冷脉冲来提供常规的瞬态传输分析。在ITB内部观察到温度的快速降低和恢复，并且发现离子热通量的变化没有改变局部离子温度梯度或改变了其他可观察到的局部参数。在两种ITB情况下，通量梯度关系显示出明显的磁滞现象：（i）电子密度梯度大的ITB和（ii）离子温度梯度小的ITB。另外，出现迟滞的范围最可能取决于ITB的宽度。