Fast potential change during sawteeth in JIPP T-IIU tokamak plasmas
Fast potential change during sawteeth in JIPP T-IIU tokamak plasmas
复制标题
JIPP T-IIU 托卡马克等离子体中锯齿期间的快速电势变化
DOI：
10.1088/0029-5515/36/4/i11
复制
发表时间：
1994
期刊：
影响因子：
3.3
通讯作者：
T. Watari
中科院分区：
文献类型：
--
作者：
Y. Hamada;A. Nishizawa;Y. Kawasumi;K. Kawahata;K. Itoh;A. Ejiri;K. Toi;K. Narihara;K. Sato;T. Seki;H. Iguchi;A. Fujisawa;K. Adachi;S. Hidekuma;S. Hirokura;K. Ida;M. Kojima;J. Koong;R. Kumazawa;H. Kuramoto;R. Liang;T. Minami;H. Sakakita;M. Sasao;K. Sato;T. Tsuzuki;J. Xu;I. Yamada;T. Watari
用重离子束探针观察了托卡马克等离子体核心区锯齿振荡过程中不同极性电势的快速变化。在反转半径附近，观测到的势的极性变化与碰撞时热核的快速运动有关，与单流体MHD理论的预测相一致。在磁轴附近，电位变化为正，在反转半径之外，电位变化为负。这与MHD的预测相矛盾。中心电子温度的周期性碰撞称为锯齿振荡，是托卡马克等离子体的常见特征。在碰撞后，观察到整个q = 1表面的压力趋于平缓。Kadomtsev提出了一个电阻重联的理论模型(7)。该理论预测了q轮廓的平坦化，以及q = 1表面内的压力轮廓。然而，这一预测被发现与最近对托卡马克等离子体电流密度的测量相矛盾(8)。此外，在JET和TFTR等大型机器上的实验表明，崩溃速度比电阻重连预测的要快得多（2-61）。现在已经提出了更精确的理论，考虑到动力学效应和遍历性对重连的影响（9-121）。本报告报告了锯齿振荡期间电位变化的第一次测量，并讨论了结果的含义。实验用JIPP T-IIU托卡马克（13）进行。它的主半径为93 cm，最大环面场为3 t。实验在相对较低的电子密度下进行，约为2 × 1013 cm3，因此可以获得良好的光束穿透等离子体中心。注入450千伏特的单电离铊束
Fast changes of electric potential with different polarities are observed during sawtooth oscil- lations in the core region of a tokamak plasma using a heavy ion beam probe. Near the inversion radius the polarity of the observed change of the potential is found to be dependent on the swift movement of the hot core at the crash and is consistent with the prediction of one- fluid MHD theory. Near the magnetic axis the change of the potentials is positive and outside the inversion radius the change is negative. This is in contradiction with the MHD prediction. A periodic crash of the central electron tempera- ture called a sawtooth oscillation is a common fea- ture of tokamak plasmas (l-61. After the crash, a flattening of the pressure throughout the q = 1 sur- face is observed. Kadomtsev proposed a theoretical model of the resistive reconnection (7). The theory predicted the flattening of the q profile as well as the pressure profile inside the q = 1 surface. The predic- tion was, however, found to be in contradiction with recent measurements of the current density in toka- mak plasmas (8). In addition, experiments in large machines such as JET and TFTR showed much faster crashes than those predicted by resistive reconnection (2-61. More refined theories, which take account of the kinetic effect and ergodicity on the reconnections, have now been proposed (9-121. The present Letter reports the first measurement of potential changes during sawtooth oscillations and discusses the impli- cations of the results. The experiment is performed with the JIPP T-IIU tokamak (13). Its major radius is 93 cm and the maximum toroidal field is 3 T. The experiment is conducted at a relatively low electron density of about 2 x 1013 cm3, so that good beam penetra- tion into the centre of the plasma could be obtained. A 450 keV singly ionized thallium beam is injected
影响因子：
3.3
作者：
A. Gibson;T. Sekiguchi;K. Lackner;S. Bodner;R. Hancox
通讯作者：
A. Gibson;T. Sekiguchi;K. Lackner;S. Bodner;R. Hancox