POTENTIAL DISTRIBUTION IN THE END REGION OF THE GAMMA10 TANDEM MIRRORASSOCIATED WITH ELECTRON FLOW-CONTROL

Potential distribution in an end region of the GAMMA10 tandem mirror i s investigated associated with experiments for control of an electron flow to a floating endplate installed on an end wall of the vacuum ves sel. The end region has an open field configuration. Mesh bias and the rmal dike experiments have been carried out in order to reduce a heat flow to the endplate by suppression of secondary electron emission fro m the endplate. Variations of the axial potential distribution in the two experiments are studied. The observed variations agree with predic tions of a theoretical potential model. This agreement shows a strong effect of the secondary electrons on the potential distribution in the end region and also indicates that the potential distribution is pred ominantly determined by axial particle transport. In this study, produ ction of Yushmanov electrons is also shown.