Experimental studies of electrostatic confinement on the intense neutron source-electron device

Abstract

Theoretical works by Barnes and Nebel [R. A. Nebel and D. C. Barnes, Fusion Technol. 38, 28 (1998); D. C. Barnes and R. A. Nebel, Phys. Plasmas 5, 2498 (1998)] have suggested that a tiny oscillating ion cloud may undergo a self-similar collapse in a harmonic oscillator potential formed by a uniform electron background. By tuning the external radio-frequency electric fields to this naturally occurring mode, it is then possible to heat the ions to obtain very high densities and temperatures simultaneously during the collapse phase of the oscillation through adiabatic compression. However, a major uncertainty in this oscillating plasma scheme is the dynamics and stability of the background electrons in the virtual cathode. Recent work based on the electron fluid equations have demonstrated that the required electron cloud is susceptible to an instability that is analogous to the Rayleigh–Taylor mode present in fluid mechanics [R. A. Nebel and J. M. Finn, Phys. Plasmas 8, 1505 (2001)]. This paper describes an inertial electrostatic confinement device at Los Alamos National Laboratory that is being used to test the electron dynamics in a virtual cathode and will subsequently be used to verify this heating and compression scheme. Results from the device operation will be presented including the formation of deep potential wells and bifurcations in the potential equilibria. A simple model is used to explain this bifurcation.