Elevated Ion Temperature in a Double-Ended Q Machine

The perpendicular ion temperature of a barium plasma contained in a double-ended Q machine has been measured by a spectroscopic technique. When the plasma is “ion-rich”, good agreement is found between the measured ion temperature and the hot-plate temperature, while in the “electron-rich” regime, the ion temperature is elevated above the hot-plate temperature. The increased ion temperature can be well accounted for by the energy input through the acceleration of ions through the electron sheath and their consequent thermalization.