Return To: Session EXP4 - Current Drive, Heating, Fuelling, Divertors
Prev Page: (EXP4/14) Recent Efficiency Improvements and Experimental Results on
Next Page: (EXP4/16) Current Drive Experiments in the HIT-II Spherical

(EXP4/15) Influence of Anisotropic Ion Heating on Confinement of the Tandem Mirror

K. Ishii¹⁾, T. Goto¹⁾, A. Itakura¹⁾, I. Katanuma¹⁾, Y. Katsuki¹⁾, T. Saito¹⁾, T. Tamano¹⁾, A. Mase^2)
 
1) Plasma Research Center, University of Tsukuba, Tsukuba, Japan
²⁾ Advanced Science and Technology Center for Cooperative Research, Kyushu University, Kasuga, Japan

Abstract.  Ion transport in the velocity space due to the Alfvén ion-cyclotron (AIC) fluctuation was investigated using a developed diagnostic device ELECA (end-loss energy component analyzer) in the tandem mirror. The AIC waves are excited spontaneously in the central cell by carrying out anisotropic ion heating with injection of the ion-cyclotron range of frequency (ICRF) wave. Hump structure was observed on the energy distribution function of the end-loss ions, and was correlated with the excitation of the AIC wave. A remarkable feature is that trapped ions with characteristic energy flow selectively into the loss region so as to cause the hump structure which appears in the energy region (1.0-5.0) keV. The AIC waves enhance the ion diffusion from the trapped region to the loss region in the velocity space, and decrease the confinement. However, it was found that the hump structure decreased in the high potential mode and the high confining potential more than 3 kV could confine a large mount of loss energy flux due to the AIC fluctuations because of the existence of the upper limit of the hump energy, even in strong excitation of the AIC wave caused by high anisotropy.

Read the full paper in PDF format.