Potential well structures in spherical inertial electrostatic confinement devices

Abstract

Inertial electrostatic confinement (IEC) devices are of interest as neutron generators for many applications. Experiments by Hirsch inspired further efforts to decipher the potential distribution within IEC devices. In this paper, previous analyzes of potential distributions in IEC devices are reviewed and extended. Three types of IEC systems are classified and analyzed according to the arrangement of electrodes and the species within the system. These systems are the unipolar cathode-anode (UCA) system, the bipolar cathode-anode (BCA) system, and the bipolar anode-cathode (BAC) system. Results of extensive parametric studies are reported through an efficient method for solving the Poisson's equation. The method is benchmarked against prior computations by Hirsch and Swanson. For BCA and BAC systems, it is concluded that the double well depth (DWD) increases as the relative focusing of the secondary particle to the primary particle increases, agreeing with prior work by Momota and Miley. Although collisions are neglected in this model, and unverified energy distributions are employed, the method generally agrees with experimental observations by Gu that the DWD will increase as the perveance of the system is increased. Thus, the computations performed here serve as a valuable benchmark.