Polywell is a proposed new type of fusion reactor, which is designed to use magnetic fields to overcome the problems with the Elmore-Tuck-Watson fusor. I'm trying to understand exactly how it works.
An Elmore-Tuck-Watson fusor ... consists of a vacuum chamber containing a negatively charged outer grid (which may be the chamber) and a positively charged inner grid. Electrons are injected into the system and accelerated toward the inner grid. Most of the time, the electrons pass through the grid, through the core, and through the inner grid again, which then decelerates them and reaccelerates them inward wherein they return through the core. As they pass repeatedly through the core, they generate a negatively charged zone, a potential well, which is called a virtual cathode.
Question 1: So this device uses a constant high voltage applied to the electrodes to produce a region of negative electric charge in the center. How is this possible? Electrons repel each other, so creating a region in empty space in which electrons are more dense than their surroundings would seem to require a constant energy input. Without any energy input, they'll just fly apart to a minimum energy equilibrium where the charge density is equal everywhere. Applying a voltage to electrodes with no current flowing between them does not use up any energy, however. So where is the energy to hold the clump of electrons together coming from?
Like the Elmore-Tuck-Watson (ETW) fusor, the polywell confines positive ions through their attraction to the negative potential well which is created by the electrons that are held inside a positively charged grid. However, to avoid the losses related to the electrons striking the grid, the Polywell uses magnetic fields to shield the grid. The magnetic fields are configured in a way that adds to the confinement of the electrons so that there are many more electrons inside the core than outside.
Question 2: So the magnetic fields generated by the grid would supposedly prevent the electrons from hitting the grid. The positively charged inner grid is attractive to electrons, but it's also magnetized, and somehow the magnetic fields repel electrons away from the grid? But how can unchanging/steady-state magnets confine (or repel) electrons? A bar magnet doesn't create any kind of movement or displacement of charge.