Ion energy containment in Heliotron-E

First measurements of the charge-exchange ion temperature in the Heliotron-E device are described. The limiting temperatures calculated from a simple energy balance equation are presented and compared with the measured temperatures. In low-current plasma, the measured temperatures agree well with the thermal conduction limit based on neoclassical theory, which includes an effect of the electron-to-ion temperature ratio Tsub(e)/Tsub(i). In high-current plasma, however, the ion temperature is about one-third of the limiting temperature. This discrepancy may be due to anomalous heat and particle transport driven by the plasma current. (author)