Measurement of profiles of the space potential in JIPP T-IIU tokamak plasmas by slow poloidal and fast toroidal sweeps of a heavy ion beam
Measurement of profiles of the space potential in JIPP T-IIU tokamak plasmas by slow poloidal and fast toroidal sweeps of a heavy ion beam
复制标题
通过重离子束的慢极向和快速环形扫描测量 JIPP T-IIU 托卡马克等离子体中的空间势分布
DOI：
10.1088/0741-3335/36/11/004
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发表时间：
1994
影响因子：
2.2
通讯作者：
I. Negi
中科院分区：
文献类型：
--
作者：
Y. Hamada;A. Nishizawa;Y. Kawasumi;K. Narihara;Kuninori Sato;T. Seki;K. Toi;H. Iguchi;A. Fujisawa;K. Adachi;A. Ejiri;S. Hidekuma;S. Hirokura;K. Ida;J. Koong;K. Kawahata;M. Kojima;R. Kumazawa;H. Huramoto;R. Liang;H. Sakakita;M. Sasao;K. Sato;T. Tsuzuki;J. Xu;I. Yamada;T. Watari;I. Negi
利用重离子束的快环向和慢极向同时扫频，以每秒120个空间分布的速率测量了JIPP T-IIU托卡马克中的等离子体势分布。提出了一种新的方法来消除大等离子体电流引起的离面入射角变化所带来的误差。关键因素之一是能量分析仪沿宽狭缝长度沿着的非常均匀的特性。一个成形的电极系统，而不是保护环与电阻链，成功地提高了分析仪的均匀性。由于在极向扫描过程中的面内入射角的显着变化的误差被仔细地最小化和校准的中性气体引入真空容器中的电离的二次光束。在欧姆等离子体中，离子温度为600 eV，在等离子体中心测得的电势的深度达到1.5 keV以上。在某些情况下，观察到相当宽的正电位区域和等离子体中心电位的急剧下降。
By the use of simultaneous fast toroidal and slow poloidal sweeps of a heavy ion beam, plasma potential profiles in the JIPP T-IIU tokamak are measured at the rate of 120 spatial profiles per second. A new method to eliminate the error due to the change of out-of-plane entrance angle caused by large plasma current is successfully applied. One of the key factors is the very homogeneous characteristics of the energy analyser along the wide slit length. A shaped electrode system, instead of guard rings with a resistor chain, successfully increases the homogeneity of the analyser. Error due to the significant change of in-plane entrance angle during a poloidal sweep is carefully minimized and calibrated by a secondary beam ionized by neutral gas introduced in the vacuum vessel. The depth of the measured potential at the plasma centre reaches more than 1.5 keV in ohmic plasmas with an ion temperature of 600 eV. In some cases, a rather wide region of positive potential and a sharp decrease of the potential in the centre of the plasma are observed.