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: more speculation on double-pulsing
Date: Nov 03, 7:14 pm
Poster: Pierce Nichols

On Nov 03, 7:14 pm, Pierce Nichols wrote:

>A god idea, but a lot of effort and imperical research would be needed to determine the optimum times and delays involved. I would imagine a near microwave frequency with long colection times might be required. This would be the result of a study of the reversal and acceleration times of the particles.

Of course, that's the fun of it . Actually, I think you misunderstand me a bit -- I'm not thinking of quickly oscillating back and forth pulsing, but a rapid series of short, discrete pulse pairs, at a rep rate of perhaps 100-200 Hz.

First, the ionization pulse, a few microseconds long, at a voltage only slightly above that of the keep-alive voltage and of high current, in order to produce the max number of ions. That is almost immediately followed by the fusion pulse, which is of much higher voltage, applied to the inner grid, and of high current. It should probably last as long as the available capacitors and power supply can make it. After that, there is a dead time of several milliseconds while the caps recharge for the next pulse.

>Reversing ions and having them ideally return might have them wind up becoming neutrals in a relatively high pressure chamber (10u). Remember, the type pressures we are dealing with are not highly conducive to a lot of recirculation. (tradeoffs.)

I don't really want to *reverse* the ions, although it seems that it might be an unpleasant result of the pulsing regime described above.

As for the pressure problems, the more I think about it the more it seems clear to me that break-even is not a possibility until the mean free path is long enough so that an ion can recirculate through the core enough times before colliding with a neutral, such that the expected value of fusion energy from it (i.e. half the energy derived from each fusion (half b/c each fusion involves 2 ions) times the probability that it will fuse before hitting a neutral) is equal to the amount of energy required to ionize and accelerate it.

This means that we will need to build fusors operating at *MUCH* lower pressures than any of the amateur efforts to date -- 10^-6 torr and below. This means an end to the convenient glow-discharge ionization, and the need to find an alternate ionization method.

>It is worth a shot for the well heeled and adventurous amateur.

Got the adventurous part down pat *g*. Working on the well-heeled part.