Diagnostics and simulation of highpressure argon and nitrogen plasma

Summary form only given. Experiments are performed using 193 nm ultraviolet (UV) laser pre-ionization of a seed gas in atmospheric pressure range argon or nitrogen to initiate a discharge that is sustained by 13.56 MHz radiofrequency (RF) power using efficient inductive wave coupling. High-density (10¹²-10¹³/cm³), large-volume (~500 cm ³) 760 torr argon plasma is initiated and maintained for 300 ms with less than 3 kW of net RF power. Using the same technique, a 50 torr nitrogen plasma with average electron densities greater than 10¹¹/cm³ is obtained. The nitrogen plasma volume of 1000 cm³ is initiated by the laser and maintained by a net RF power of 5.5 kW for 300 ms. Measurements of the time-varying plasma load impedance and optimization of the RF matching for the transition from laser-initiated to RF-sustained plasma are carried out. Millimeter wave interferometry is used to determine the electron density and effective electron collision frequency. A new diagnostic technique based on interferometry is developed to measure the electron temperature in high pressure plasmas. Broadband plasma emission spectroscopy is used to illustrate the changes in the broad ionized species character immediately after the laser pulse and later during the RF pulse. Advanced RF impedance measurement and RF tuning techniques are developed to enhance RF matching of the inductively coupled plasma source to the RF system. Computer simulation of the interferometry diagnostics of plasma density and collision rate is performed. Results of a new focused-laser generated plasma near a microwave dielectric window are also presented