Neutral-Beam Heating in the Adiabatic Toroidal Compressor

Experiments have been conducted on an adiabatic toroidal compressor with tangential injection of two 14-15-keV, 3-4-A beams of ${\mathrm{H}}^0$ or ${\mathrm{D}}^0$. The ion-temperature rise for both ${\mathrm{H}}^{+}$ and ${\mathrm{D}}^{+}$ plasmas is 70-80 eV (i.e., 35-40%), consistent with theoretical expectations for charge-exchange-limited energy transport at neutral-atom densities ≅ ${10}^9$ ${\mathrm{cm}}^{-3\mathrm{}}$. The injected ions are found to decelerate in agreement with classical theory and produce an initial plasma ion heating rate of ∼ 20 keV/sec.