Characterization and Overview of the HELCAT (HELicon-CAThode) Dual-Source Linear Plasma Device

The HELCAT (HELicon-CAThode) device is a dual-source linear plasma device that has recently begun full operation at the University of New Mexico. HELCAT is 4 m long, 50 cm diameter, with axial magnetic field $<$ 2.2 kG. An RF helicon source of tunable frequency 10 -- 30 MHz and P $<$ 5 kW, resides at one end of the device, while a thermionic BaO-Ni cathode capable of discharge currents up to 2.5 kA is located at the other end. Nominal parameters are: Te $\sim$ 5 -- 10 eV, ne $\sim$ 10$^{12}$ /cc (cathode), 10$^{13}$ -- 10$^{14}$ /cc (helicon), plasma diameter 15 -- 20 cm. Diagnostics now online include electrostatic and magnetic probes, mm wave interferometry, visible spectroscopy, and LIF. Several basic plasma physics experiments are underway, including active feedback control of turbulent transport, physics of edge convective transport, Alfven wave-neutral particle interactions, and physics of expanding high density magnetized plasma ``bubbles'' in the background discharge. An overview of the device characteristics and initial experimental results will be presented.