A polywell (right) uses six Magnetic coils, arranged in a positive polyhedral (cubic) grid, called a Magrid, to create a concentrated cloud of electrons, called a Potential Well, at its center.  The setup operates in a Vacuum Tank, which prevents electrical arcing and interference from air molecules.  Negatively charged electrons, fired from Electron Guns, are attracted by the positively charged magrid.  The electrons fly at high speed through the centers of the donut holes in the magrid.  The magrid’s magnetic field keeps the electrons away from the magrid and trapped in the center.  “Polywell” is short for polyhedral potential well.


Each of the magrid’s “donuts” is really a coil of electric wire (left).  When an electric current is applied to the wire in the coils, a magnetic field is created. The magnetic field does two things, it keeps the electrons concentrated in the potential well, and it shields the positive magrid coils from the electrons.   If the electrons collided with the positively charged magrid they would be lost, and the electron-storing efficiency of the polywell would be compromised.

Here’s a “cut-away” view of a slice through the center of the magrid (right).  You can see the black potential well of electrons at the center; and you can see the dotted-line magnetic fields created by the coils of wire.  If the electrons run into a magnetic field when they try to escape from the potential well, they will be deflected back into the well, as per our earlier discussion.  However, if you look at Tom Ligon’s drawing carefully, you can see that there are eight potential pathways for escaping electrons, where the lines of force will NOT be perpendicular to the electron motion.  These escape pathways are called cusps.

If an electron’s motion closely parallels the magnetic lines of force – as it would in escaping through a cusp – it will still be deflected somewhat by the magnetic field, but now it will be forced into a spiral that follows the magnetic lines of force out of the magrid, and around one of the coil cross-sections.  Electrons that spiral along the magnetic lines of force out of the magrid and back in again, are said to be circulating.

When the electrons are first shot into the center of the magrid, they circulate easily, following the lines of force in and out of the magrid (below left – the electrons are shown as black dots).  At first, all the magnetic lines of force loop through the center of the magrid, so the electrons are naturally more concentrated at the center of the magrid.  This concentration has the effect of pushing the magnetic field away from the center, squeezing the magnetic lines of force against the magrid (below right).

When the lines of force are pushed against the magrid, the cusp “escape paths” are squeezed into a much smaller size, and the electrons can no longer circulate as easily.    This newly formed sphere of confinement is called a Whiffle Ball™.  The electrons bounce violently back and forth inside of it, trying to escape.

Picture a real Wiffle Ball™ with a few marbles inside.  The marbles are very close to the diameter of the holes in the Whiffle Ball™.  If you shake the Wiffle Ball™ violently, a few marbles will fall out from time-to-time; but mostly, they will just bounce off the walls of the Wiffle Ball™.  The marbles are the electrons, the Wiffle Ball™ is the magnetic confinement, and the holes are the cusps.  Every once in a while, an electron will escape, but when it does, it will just spiral its way along a magnetic line of force, and back into the magrid again.