Study of Potential Structural Reformation with multi-channel measurements using heavy ion beam

在2000年至2001年的前两个财政年度，我们在中国科学院建造了一个新的重离子束探测器(HIBP)系统，除了旧的HIBP系统。新的HIBP位于环向与旧HIBP相差90度的位置。在此期间，我们还进行了实验，以进一步了解分叉特性。在这些实验中，我们获得了关于分叉模式和滞后存在的新发现，以实现改进约束的状态。这些结果已发表在《核聚变》杂志上。此外，包括CHS在东山站点时所获得的结果的综合论文也发表在《等离子体中的分叉现象》一书中。在2001财政年度，新的HIBP的建设已经完成，并使用两个HIBP系统在ECR加热的低电子密度0.5x10^&lt；13&gt；cm^&lt；-3&gt；的CHS等离子体上进行了第一次实验。这两个HIBP在两个不同径向位置的同时测量给出了电脉冲(自组织振荡)中势结构的时空演化信息。这一结果已在第19次国际原子能机构聚变能源会议上以死线后论文的形式公布。结果表明：1)脉动过程中，电势降由中心向外传播，传播速度较快；如果将传播过程表示为扩散过程，则系数为D-100m^2/S。2)发现边缘密度与中心势行为密切相关。观察到了这种现象的非局域性，III)在同一系列放电中，观察到了电势的相干起伏。认为涨落与Alfven模有关，并推导出相应的磁面位移。

In the first two fiscal years from 2000 to 2001, we had constructed a new heavy ion beam probe (HIBP) system on CHS in addition to the old HIBP system. The new HIBP is located at the position away from the old one by 90 degree in toroidal direction. During this period of the construction, we had also made experimental efforts to obtain further understanding of bifurcation characteristics. In these experiments, we have obtained new findings about patterns of bifurcation and existence of hysteresis for realization of the status with improved confinement. These results have been published in Nuclear Fusion. Furthermore, the integrated paper including the results obtained in the phase when CHS is in the Higashiyama site has been also published in the book entitled 'Bifurcation phenomena in plasmas'. In the fiscal year 2001, the construction of the new HIBP has been finished, and the first experiments using two HIBP systems have been done on the ECR-heated CHS plasma with a low electron density of 0.5x10^<13> cm^<-3>. The simultaneous measurements at two different radial positions with these two HIBPs give us information of spatio-temporal evolution of potential structure during electric pulsation (self-organized oscillation). The result has been presented as a post dead line paper in 19^<th> IAEA conference on fusion energy. The outline of the results is following, i) During the pulsation, the potential drop propagates from the center to the outside, and the propagation is quite high. If we express the propagation as diffusion process, the coefficient is D-100m^2/s. ii) It is found that the edge density is strongly correlated with central potential behavior. The observation shows non-local nature of this phenomenon, iii) In the same series of discharges, coherent fluctuation has been observed in potential. The fluctuation is considered to relate with Alfven modes and the corresponding displacement of magnetic surface has been deduced.