Air constituent plasmas produced by a radiofrequency plasma source

Summary form only given, as follows. A radiofrequency plasma source is used to study the creation and sustainment of a high density plasma of air constituents (N/sub 2/, Ar, and O/sub 2/). Various antenna configurations, including helical antennas, are used in conjunction with a capacitive matchbox system and a broad-band (2-200 MHz), high power (1 kW) amplifier to couple power to the plasma. A calibrated Bird meter at the matchbox allows for real-time monitoring and measurements of forward and reflected power. The role of antenna configuration, applied magnetic field (100-1400 G), operating frequency, and gas concentrations on the power coupled to the high density (10/sup 11/-10/sup 13/ cm/sup -3/) plasma have previously been examined at lower gas pressures (10-100 mTorr), and these results are extended to higher pressure regimes. Antenna configurations, including multiple turn coils and variations on helical antennas, are tested to maximize power coupling to the plasma at pressures in the Torr range. Initial experiments at pressures of 1 Torr indicate a mixture of argon and nitrogen produces a plasma which exhibits synergistic power coupling features different than the cases of pure N/sub 2/ or pure Ar plasmas at the same pressure and input power. This phenomenon is explored to determine if a seed gas is beneficial to the breakdown of air constituents. Plasma density is measured by interferometer methods, and the wave B-field is measured by a B-dot probe. Network analyzer measurements are made on the power coupling system to determine antenna impedance values. The experimental results are compared with simulation results from ANTENA2 and MAXEB codes. A photomultiplier tube and spectrometer is used to examine plasma lifetime and emission spectra, providing insight into the chemical and physical processes in air constituent plasmas.