Heat flow diagnostics for helicon plasmas

Daniel F. Berisford, Roger D. Bengtson, Laxminarayan L. Raja, Leonard D. Cassady, William J. Chancery
2008 Review of Scientific Instruments  
We present experimental studies of power balance in an argon helicon discharge. An infrared camera measures the heating of the dielectric tube containing a helicon discharge based on measurement of temperature profiles of the tube surface before and after a rf pulse. Using this diagnostic, we have measured surface heating trends at a variety of operating conditions on two helicon systems: the 10 kW VASIMR VX-50 experiment and the University of Texas at Austin 1 kW helicon experiment. Power
more » ... eriment. Power losses downstream from the antenna are measured using thermocouples and probes. The heating of the dielectric tube increases with decreasing magnetic fields, higher gas flow rates, and higher molecular mass of the gas. These preliminary results suggest that cross-field particle diffusion contributes a significant proportion of the energy flux to the wall.
doi:10.1063/1.2955710 pmid:19044660 fatcat:i4ez2ioqpncwjmuv3f3stdo3xi