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: Fusor uses for microwaves:
Date: Aug 18, 2:17 pm
Poster: Mark Sloan

On Aug 18, 2:17 pm, Mark Sloan wrote:

Fusor uses for microwaves:

Mainstream fusion designs often use microwaves for 1) Plasma Heating (megawatt power ranges for their big volumes of plasma) and 2) Plasma Diagnostics (much lower power ranges?). These are interesting, but I don't see a way to use them directly to get big increases in IEC fusion efficiency rates. (Except just as something to try to see if anything interesting happens.)

I wondered if microwaves could be used in a third way (suggested in a previous note of mine). This use would be to excite a spherical resonance using microwaves in the central plasmoid of an IEC like device. Every oscillation, the + ions in the plasmoid would undergo a compression, a "crunch" at the center, followed by an expansion, followed by a compression and a crunch, and so forth. The concept was that if the oscillation could drive the ions to a 10 to 20 Kev kinetic energy range, then in the crunch, there would be a high density of ions making head on collisions with the right energies for fusion. It would produce a very non-Maxwellian energy and direction distribution (fusion in velocity space?) that is at the core of the IEC approach.

But I now realize that the microwave oven wavelength (12 cm or 2.45 gighz) is much too short. It would allow convenient size resonant (metal) cavities, but does not give the plasmoid enough time to expand and contract.

Assuming that at the "crunch" the fusor plasmoid deuterium ions have 20 KEV of kinetic energy, then I calculate their velocity is 1.38 X 10E6 m/s or about 0.5% of the speed of light. Perhaps the average expansion and contraction velocity is this. Then the plasmoid would have time to contract or expand only 0.015 cm in a cycle (distance = (ion velocity/velocity of light) X distance light travels in cycle = X 0.5% X X 12 cm). This seems much too small.

More realistic plasmoid oscillation diameters might be about 1 cm at the crunch and 7 cm at maximum expansion. This would need a RF frequency about 400 times lower or 6 meghz to drive it. This wavelength (equivalent to 50 m) makes resonant chambers too big to be useful, but a resonant chamber is not necessarily required.

There may not be anything worth pursuing here, but I wanted to clarify the idea.