Space charge neutralization in inertial electrostatic confinement plasmas

Abstract

A major issue for electron injected inertial electrostatic confinement ͑IEC͒ devices is space charge neutralization. A new formalism is developed that will allow this neutralization to occur for both oscillating and steady-state IEC plasmas. Results indicate that there are limits on the amount of compression that can be achieved by oscillating plasmas while simultaneously maintaining space charge neutralization and parabolic background potential. For steady-state plasmas, there are no such limits and space charge neutralization can be achieved even when the plasma becomes quasineutral.

Oscillating ions under Inertial Electrostatic Confinement (IEC) based on nanosecond vacuum discharge

“…), were recognized in early NVD experiments . Apparently, in our steady‐state plasmas in the NVD device, the POPS‐like oscillations are primarily a mechanism to resonant heat the ions (similar to the one discussed at the end of paper) rather than for coherent compressions, as originally envisioned for POPS . In addition, our system with the deep PW satisfies the stability conditions discussed in as ion “temperature” is comparable to the electron injection energy .…”

“…Stability of large‐amplitude plasma oscillations in IEC devices was predicted earlier in . Note that, in paper , a systematic approach is used in order to determine how to best inject electrons into an IEC system like POPS or steady‐state device. Concerning our NVD with cylindrical geometry, we avoid some restrictions or limits caused by geometrical convergence in the sphere .…”

“…Note that, in paper , a systematic approach is used in order to determine how to best inject electrons into an IEC system like POPS or steady‐state device. Concerning our NVD with cylindrical geometry, we avoid some restrictions or limits caused by geometrical convergence in the sphere . In addition, we must remember that electron injection in our discharge automatically moves from the cathode surface to Pd tubes' anode space when the voltage is applied, and observed deuterons oscillations (through pulsating neutron yield ) are rather stable or even increasing also (Figures and ).…”

Spherical ion oscillations in a positive polarity gridded inertial-electrostatic confinement device

“…1 A major source of uncertainty in the POPS methodology yielding appreciable fusion returns stems from the requirement for the explicit maintenance of a uniform electron space charge, at a fixed energy distribution. 12 The mitigation of space charge effects became a focus of POPS related research, in ultimately requiring the careful maintenance of a fixed electron energy and density distribution through sophisticated emission schemes to achieve large peak ion densities. Theoretical treatments 13 predicted that volumetric compression ratios of 1000:1 are required for the achievement of breakeven energy generation.…”

“…Mitigating these space charge limitation effects to achieve such high compression ratios requires the injection of a carefully programmed Gaussian electron distribution. 12 This electron distribution would need to be superimposed on the uniform density electron cloud that is seeded as a harmonic oscillator attractor. The oscillations described in the course of this paper are assumed to be contingent on the harmonic spherical traversal of ions from grid adjacency to the central region in an approximately radial fashion, with aberrations seeded from spherical asymmetry akin to a RayleighTaylor fluid instability yielding radial channels for electron counter-streaming.…”