| AVS 63rd International Symposium & Exhibition | |
| Plasma Science and Technology | Thursday Sessions |
| Session PS-ThP |
| Session: | Plasma Science and Technology Division Poster Session |
| Presenter: | Chenhui Qu, University of Michigan |
| Authors: | C. Qu, University of Michigan P. Tian, University of Michigan M.J. Kushner, University of Michigan |
| Correspondent: | Click to Email |
Arrays of microplasmas are being investigated to manipulate electromagnetic waves. Such applications require control of the electromagnetic properties of individual plasma cells. Motivated by the tradeoff between fast response and high plasma density, the optimum operating range for the plasma includes pressures from 10s to 100s Torr, and so the scale of each cell shrinks to 100s μm due to pd scaling. Controlling cross-talk is a major challenge in design of microplasma arrays since plasma cells are not separated by physical barriers as in conventional plasma-display-panels. This lack of physical barriers is necessary in order to reduce the loss or scattering of incident electromagnetic waves.
Small 2-dimensional arrays of microplasmas are being computationally investigated with the goals of maximizing electron densities while minimizing cross-talk between plasma cells. The microplasma arrays are sustained in 10s to 100s Torr of rare gas mixtures excited by dc-unipolar pulses. The small arrays contain 4 to 9 plasma cells.
The base case geometry contains four plasma cells operating in 60 Torr Ar powered by 300 V peak value unipolar pulses having a 10 MHz pulse repetition frequency and 30% duty cycle. The width of the array is 320 μm and the length is 830 μm, conditions which produce maximum electron densities up to 2 × 1014 cm-3 with a cathode fall region forming near the exposed cathodes. Beam ionization by secondary electrons contributes ≈65% of the total ionization during the pulse on period. Cross-talk between plasma cells does not significantly affect the performance of individual plasma cells even though they are not physically isolated. The predicted plasma properties are used to evaluate the potential for controlling electromagnetic wave properties when propagating through large arrays of such microplasmas. The electromagnetic simulator HFSS was used to investigate microwave propagation through the microplasma array, including control of the magnitude and polarization of the electric field.
Work was supported by Air Force Office of Scientific Research, Department of Energy Office of Fusion Energy Science and the National Science Foundation.