Collisional Relaxation of Non-Maxwellian Plasma Distribution in a Polywell (Tradename)

The Polywell is a magnetic version of a Spherically Convergent Ion Focus (SCIF) device which was proposed as a significant variation of earlier studies on electrostatic confinement. The idea of this device is to inject high energy electrons into a quasi-spherical magnetic field; the electrons create a potential well of sufficient depth to accelerate ions from low energy at the periphery to fusion energies within a focus at the center of the sphere. Injection of electrons keeps the system electrically nonneutral, so that the potential well which accelerates the ions is maintained at a constant value sufficient to confine the ions within the device, returning them again and again at high velocity to the central focus. Essential to the success of the scheme is that the ions maintain their nonthermal velocity distribution, with primarily radial flow, long enough to produce fusion in the dense focus at the center of the sphere.