Novel diagnostic approaches to characterizing the performance of the Wisconsin inertial electrostatic confinement plasma

The inertial electrostatic confinement (IEC) device confines energetic ions in a spherically symmetric, negative potential well between two nearly transparent metallic grids. Diagnostics were developed and implemented to understand IEC device operation.;A plasma diagnostic to measure concentrations of molecular deuterium ions in the edge plasma region of the UW-Inertial Electrostatic Confinement (IEC) fusion device was developed and implemented. This diagnostic measured the phase velocity of multi-species ion acoustic waves in the source plasma of the UW-IEC device. It was concluded that the source plasma, when run with deuterium fuel, is dominated (>50% by ion density) by D3 + ions.;A fusion product Doppler shift diagnostic for the measurement of energetic deuterium velocity spectra within the intergrid region of an inertial electrostatic confinement fusion device was developed and implemented. The diagnostic measured the Doppler shift imparted to high energy fusion protons from the deuterium reactants within the device. This work measured, for the first time, the high energy deuterium spectra within an IEC device. This diagnostic documented the deuterium spectra variations over a wide range of device parameters. A dominant fraction of the energetic deuterons had energies between 10-20 keV for cathode potentials between 50-100 kV.;A technique to resolve the location of the fusion reactions along a chord through the center of an inertial electrostatic confinement fusion device was developed and implemented. Two opposed silicon charged particle detectors determine the fusion reaction location by recording the difference in arrival time between the high energy proton and triton resulting from a D-D fusion reaction. Preliminary results indicate that, at 50 kV, 30 mA, and 2 mTorr of neutral gas, 50% of the fusion reactions occur within the 10 cm radius cathode of the UW-IEC device.;A magnetic deflection energy analyzer and Faraday trap diagnostic were used to measure divergent negative ion flow in the UW-IEC experiment. Energy spectra obtained using a magnetic deflection energy analyzer diagnostic indicate the presence of D2-, and D- ions are produced through charge transfer processes, and thermal electron attachment. These negative ions can account for up to 30% of the fusion rate.