Lithium Ion Sources for Investigations of Fast Ion Transport in Magnetized Plasmas

In order to study the interaction of ions of intermediate energies with plasma fluctuations, two plasma immersible Lithium ion sources of different size, based on solid–state thermionic emitters (Li-6 Aluminosilicate), were developed. Compared to discharge based ion sources \footnote{H. Boehmer et al., Rev. Sci. Instrum., 75, 1013 (2004)}, they are compact, have zero gas load, small energy dispersion, and can be operated at any angle with respect to an ambient magnetic field of magnitude generally found in plasma experiments. Beam energies range from 400 eV to 2.0 keV with typical beam current densities in the 1 mA/cm2 range. Because of the low ion mass of 6 amu, beam velocities of 100--300 km/s are in the range of Alfv\'{e}n speeds in Helium or Hydrogen plasmas. Design considerations and operation in a high vacuum test chamber as well as in the high density, magnetized plasma of the LArge Plasma Device (LAPD) at UCLA will be detailed.