Fusion Message Board

In this space, visitors are invited to post any comments, questions, or skeptical observations about Philo T. Farnsworth's contributions to the field of Nuclear Fusion research.

Subject: Re: Bussard and his catch 22
Date: Oct 19, 5:45 pm
Poster: Tom Billings

On Oct 19, 5:45 pm, Tom Billings wrote:

>I've been thinking about the Bussard device and its magnetically protected grid.
>In my opinion the magnetic protection will eventually increase the scattering of the particles. The reason is because the magnetic field reflects particles, but an even larger problem is going to be heat.
>No grid can stand the kind of inferno that the IEC device will be creating at higher power levels. It will be interesting to see how Bussard will get around these problems without making a Frankenstein IEC device that always needs more of this and more of that to break even.

If he were speaking of an inner grid, you'd be correct. I have in my lap a copy of Bussard's March 1991 paper in Fusion Technology, describing the polywell system. It does not speak of protecting an inner grid, but of replacing it with a 'quasi-sphere' of electrons, constrained by a magnetic field for long periods.

This allows the low mass/momentum electrons to keep a negative charge cloud around the center of the chamber, which is constrained by a magnetic field which will not scatter the high mass/momentum ions to any extent which would drive up losses intlolerably. This allows the losses due to the collisions of ions and any inner grid to be completely avoided. A key question is whether the electrons will have a sufficiently long life, in their quasi-spherical magnetic confinement, to keep the power loss from adding new electrons far lower than the loss from ion collisions in gridded systems.


Tom Billings