HL-lM装置杂质粒子输运与约束特性

摘要

在HL-lM装置上利用激光吹气技术，在等离子体边缘瞬态注入少量Al杂质粒子，通过对真空紫外光谱和软X射线区的杂质辐射测量，分别研究了欧姆等离子体和低杂波电流驱动等离子体两种情况下，Al杂质粒子输运与约束特性。结果表明：在欧姆等离子体和低杂波电流驱动等离子体两种情况下，等离子体中心区，在没有MHD锯齿震荡和有MHD锯齿震荡非锯齿破裂期间，杂质粒子输运基本上受新经典规律支配；在有MHD锯齿震荡锯齿破裂期间，杂质粒子输运受MHD不稳定性支配，但其时间很短(通常小于300μs)，所以在这种情况下，杂质粒子输运的平均效应比新经典值稍大。而约束区杂质粒子输运则比新经典的值大很多，是反常的。在一定条件下低混杂波电流驱动可以改善等离子体粒子约束。%the features of Al impurity transport and particle condinement have been studied with transient impurity injection at plasma edge in Ohmic discharge and low hybrid current drive on HL-lM tokamak respectively. A small amount of Al impurity was injected using laser below-off technique. The impurity spectrum and soft X-ray intensity were measured with VUV spectroscopy and with soft X-ray camera respectively. The studies show that in the core regime the impurity transport could be described by new-classical theory in the sawtooth-free discharges or in the sawtooth discharger except the sawtooth crash in both cases basically. During the sawtooth crash the impurity transport could be controlled by MHD instabilities in the core region. The effective time is so short(less than 300μs usually) that the average transport coefficients of the impurity transport is slight higher than that calculated from new-classical theory in the core region. In the confinement range the impurity diffusion coefficient is much higher than that estimated with new-classical theory. The impurity transport is anomalous. the particle confinement could be improved in a certain condition during the low hybrid current drive.