Radiofrequency sustainment of a laser-produced plasma

Summary form only given, as follows. A plasma is generated by photoionization of the organic seed molecule tetrakis(dimethylamino)ethylene (TMAE) and is sustained by RF coupling through the use of an antenna. Collisional ohmic heating is studied as various gasses are introduced and pressures varied over several orders of magnitude up to atmospheric pressure. The physics involved in waves and fields generated by the antenna is highly dependent on the working gas and pressure. This has a substantial effect on the radiation resistance of a multiple turn helical coil which is utilized to maintain the discharge. A strong magnetic field is introduced to determine if field penetration is affected. Plasma densities of the order 10/sup 13/ cm/sup -3/ are obtained in a 2.5 cm radius tube. The computer codes ANTENA2 and MAXEB are used to help model the results. TMAE gas is being investigated as a possible seed gas for initiating atmospheric pressure air plasmas because the plasma can be initiated with a high-density initial condition which has been shown to enhance power coupling to the bulk plasma.