Spherical plasma oscillations in a reversed-polarity inertial-electrostatic confinement device

A pulsed reversed-polarity inertial-electrostatic confinement device has been investigated experimentally using voltage and spectroscopic diagnostics. Large-amplitude oscillations were observed in the floating potential of the plasma immediately following the initiation of the discharge. It is postulated that the observations were the result of coherent ion oscillations within a harmonic potential well formed by a uniform electron density in the center of the device. A simple model of the system predicts the depth of this transient potential well to be approximately 100 V. Observations of the relative occupation of the third and fourth energy levels of hydrogen in the plasma indicated the formation of a Maxwellian electron energy distribution after 20 μ s . The results suggest a promising avenue toward a net fusion power gain by utilizing these oscillations to periodically compress and heat the plasma to thermonuclear densities and energies.