Laser and radiofrequency air plasma sources

Summary form only given, as follows. We are carrying out plasma source research utilizing 193 nm laser ionization of an organic gas (Tetrakis-dimethyl-amino-ethylene) in constituents of air (N/sub 2/, O/sub 2/) and other gas (He, Ar, Xe) components. Microwave scattering, fast Langmuir probe and photodiode measurements are used to diagnose the plasma formation and decay. Initial peak plasma densities of 5/spl times/10/sup 13//cm/sup 3/ are obtained with volumes of 10 cm/spl times/5 cm/spl times/20 cm. Results of these measurements with an emphasis on the role of the addition of air and other gas constituents on plasma lifetime will be presented. A comparison of the experimental results with air plasma chemistry codes will be discussed. We have analyzed, designed and constructed a plasma radiofrequency source to examine highly collisional plasma production and sustainment of a laser produced plasma. Wave modelling results utilizing the ANTENA II and MAXEB codes in the 2-200 MHz range show that a moderate magnetic field can enhance wave propagation and absorption away from the antenna coupling region for highly collisional plasma sources. We examine the role of metastable atoms and electron attachment and detachment processes for our 1-3 kW radiofrequency plasma source sustainment experiments for different Ar, N/sub 2/ and O/sub 2/ gas components. The use of the laser for creation of accurate plasma density spatial profiles which are sustained by the radiofrequency source for air plasma will be discussed.