Electrostatic-Inertial Plasma Confinement

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Abstract
Electrostatic‐inertial plasma confinement consists of trapping charged particles in potential wells of the electric field, which are created by ions or electrons injected radially inwards into a hollow sphere or cylinder. Theoretical expressions are derived for the potential and particle densities as functions of radius, grid voltage, and current. A neon plasma is produced in cylindrical geometry, using a grid 4 cm in diameter and 16 cm long. Using the laser heterodyne technique at 0.6401 and 0.6328 μ, the density of neon atoms in the 1s5 metastable state is measured (109−1012 cm−3) as a function of radial position, time, grid current (20 ‐ μsec pulses of up to 4 A), grid voltage (0.2–3.0 kV), gas pressure (0.001–0.01 Torr), and grid mesh spacing, and compared with theoretical predictions. The peak electron density is 1011 cm−3. When the spacing between grid wires is larger than 1 mm, a decrease in metastable density, attributed to the presence of a plasma sheath around the grid wires, is observed. The radial variation of plasma light intensity is compared with the theoretical radial distribution of electron density.