measurements of convective-cell structures in the Proto-Cleo stellarator were not conclusive [6]. In this paper, we compare cross-field and tangential plasma injection in the Proto-Cleo stellarator to demonstrate the role of injection in convective-cell formation. The results show that a significant improvement in confinement occurs with tangential plasma injection.ABSTRACT. Gun injection of plasma parallel to the magnetic field in the Proto-Cleo stellarator results in particle confinement times of 3.5 -4 ms while injection of plasma perpendicular to the magnetic field results in confinement times of 1.5 -2 ms. Calculations of confinement times based on convective-cell theory that includes shear show good agreement with experimentally measured values.

Effect of temperature on the emission characteristics of liquid metal alloy ion sources Direct current and pulsed operation of contaminated liquid metal ion sources Stable field-induced electron emission from a solidified liquid metal ion source Appl. Phys. Lett. 72, 389 (1998); 10.1063/1.120745 Minimum emission current of liquid metal ion sourcesThe analytical energy distribution for the ions emitted at the protrusion apex surface of an anode is obtained from field evaporation theory. The distribution profiles are a kind of shifted exponential asymmetry function having a sharp increase and exponential decay. These asymmetric profiles are seen in many experiments. The full width at half maximum of ion energy distribution at the emission surface is about that of thermal energy (ϳkT), while the measured values by the energy analyzer located beyond the diode are typically of the order of ϳeV. The influence of emission current and temperature at the emission surface on the energy-distribution profiles at the end of the diode will be investigated. It is found that the energy spread increases from the thermal energy of kT at the emission electrode to a value of the order of eV as the ions propagate from the anode to the cathode.