| Plasmas are gases composed of electrons, ions, and neutral species. Typically, the electrons and heavy species are in thermal non-equilibrium, and impact by energetic electrons breaks the feedstock gases into desired products. The plasma hydrodynamics is studied by solving Maxwell's and transport equations in 2-d unstructured meshes. A plug-flow model is used for large reaction chemistries. In this thesis we look at the following problems:;Oxygen-iodine lasers are used in defense applications, and in metal cutting. Collisions between O2(1Delta) and I produces the I* (1.315 mum), and the fraction of O2 in the 1Delta state (yield) determines the efficiency. The yield is a function of discharge efficiency (He/O2 mixture), although it scales sub-linearly with power due to dissociation. O2(1Delta) production is efficient at electron temperatures (Te) of 1-1.5 eV, and uniform power deposition, addition of NO improves this efficiency. O atoms are detrimental to the laser, and they are managed by adding small amounts of NO/NO2 which recoup O atoms. The optical gain in the laser cavity is optimized using parameters like flow rates of NO/NO2, I2 for a given power.;An in-situ creation of H2 using NH3 microdischarges is explored for use in portable fuel cells. Electron-impact reactions and neutral chemistry in the afterglow are important sources of H and H2 . Te significantly affects the dissociation of NH3 especially at low NH3 concentrations. Conversion of NH3 is efficient at lower flow speeds, and higher energy deposition per NH3. A tradeoff exists between the energy required to create a H2 molecule and number of H2 molecules produced per NH3.;Small satellites (few kg) require muN - mNs thrust for station keeping with nominal power requirements (few Watts). MDs deposit power to flowing Ar (at 10s Torr), and the incremental velocity, gas temperature, and thrust are studied. Due to the large surface-to-volume ratio and low Reynolds number, heat conduction to the walls and viscous losses play a significant role in determining thrust. Geometrical parameters like nozzle length and angle, and flow parameters such as power, pressure, and flow rate can be used to optimize the thrust. |
