A passive method to trap an electron beam in a stellatron accelerator

Abstract

An electron beam can be trapped in a stellatron accelerator with a passive technique by dissipating the energy associated with the poloidal displacement of the beam from its equilibrium position. If the net force on the beam is directed toward the minor center of the vacuum chamber, the beam will spiral toward its equilibrium position. The beam dissipates energy by charging and discharging a conductor that is grounded through a resistor. Numerical solutions in the paraxial approximation illustrate this capture effect, with parameters that show a large enough effect to trap a beam.

Steady state formation of a toroidal electron cloud

“…A few examples are electrostatic thermonuclear fusion reactor [7], heavy ion accelerator [8], source of highly stripped heavy ions [9], modified betatron [10], and stellatron [11]. The concept of a totally non-neutral ion torus, where high energy ions are confined by their own space charge field, may, being relatively free of transport losses of conventional neutral plasma, lead to an ideal thermonuclear reactor; however, this idea requires further quantitative examination, In all the earlier experiments, electron injection was achieved by the so-called inductive charging process [4] based on the principle that, in the guiding center approximation, both the electrons and the magnetic flux lines in an inductor move in the direction of Poynting's vector with the common (E x B)/S^ velocity.…”