Studies of waves and instabilities using increased beta, warm ion plasmas in LAPD*

A new plasma source based on a Lanthanum Hexaboride (LAB$_6$) emissive cathode has been developed and installed on the LArge Plasma Device (LAPD) at UCLA. The new source provides a much higher discharge current density (compared to the standard LAPD Barium Oxide source) resulting in a factor of $\sim 50$ increase in plasma density and a factor of $\sim 2-3$ increase in electron temperature. Due to the increased density the ion-electron energy exchange time is shorter in the new plasma, resulting in warm ions (measured spectroscopically to be $\sim 5-6$eV, up from $\alt 1$eV in the standard source plasma). This increased pressure combined with lowered magnetic field provides access to magnetized plasmas with $\beta$ up to order unity. Topics under investigation include the physics of Alfv\'{e}n waves in increased $\beta$ plasmas (dispersion and kinetic damping on ions), electromagnetic effects and magnetic transport in drift-Alfv\'en wave turbulence, and the excitation of ion-temperature-anisotropy driven modes such as the mirror and firehose instabilities. The capabilities of the new source will be discussed along with initial experimental resuls on electromagnetic drift-Alfv\'{e}n wave turbulence and Alfv\'{e}n wave propagation with increased plasma $\beta$.