Steady state formation of a toroidal electron cloud

Abstract

A novel scheme of injection and confinement of electrons is reported for the formation of a toroidal electron cloud in the presence of a static toroidal magnetic field. The scheme is based on the use of a combination of externally applied electric field and the self-consistent space charge field for the electron trapping and confinement. The time development of electron cloud potentials measured in the poloidal plane of the torus is presented. A potential well depth exceeding the initial kinetic energy of the electrons is observed, indicating collective effects. The effect of external field on the total charge and capacitance of the electron cloud is also presented.

2-D Guiding Centre Simulation of Toroidal Electron Clouds

“…A biquadratic spline interpolation scheme is then used to interpolate the electric field components from grid moving in the poloidal plane. This is consistent with the experiments [4] to be analysed as they were performed in points to particle locations. This approach of calculating the electric field is different from the method used in [6].…”

“…The plasma is observed to reach a steady state which is shifted radially inwards with respect to the minor axis. This inward in understanding the complex self consistent motion of shift is due to toroidal effects as it is found to increase when the electron structures observed in the experiments [4]. The aspect ratio of the torus is decreased.…”

“…We have initiated a series of experiments to study the basic properties of low A 2-D electrostatic particle simulation code has been developed to study various processes in toroidal electron clouds that occur aspect ratio A (A ϭ Major radious R 0 /Minor radius a) on time scales much longer than the electron cyclotron period.toroidal electron clouds [3,4]. The present code has been This code can be applied to gain insight into k ʈ ϭ 0 experimental developed to study the evolution of such a toroidal electron phenomena encountered in toroidal electron plasmas.…”

Parameter Dependence of Inward Diffusion on Injected Electrons in Helical Non-Neutral Plasmas

“…Several methods had been used to inject the electrons in toroidal geometry([3]- [4]). Recently, a new method of injecting electrons through a stochastic magnetic layer has been performed [5] on the Compact Helical System (CHS) device [6].…”

Injection of electrons into a toroidal trap using chaotic orbits near magnetic null

“…This method cannot be used in a toroidal system that does not have open ends of field lines. In earlier toroidal experiments, some different methods of injection, such as use a rising toroidal magnetic field ('inductive charging method' [4]) or use a drift motion of particles [5] were invented.…”