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 04, 6:34 pm
Poster: Pierce Nichols

On Nov 04, 6:34 pm, Pierce Nichols wrote:

>No, this is exactly what I was thinking, but I feel the pulses may work out to be a lot shorter (nanosecond level) in small devices. I figured on a low rep rate, high current small pulse width. RH

According to the Miley quotes posted, below 100 Hz rep rate doesn't really get any gain. I suspect that pulse widths shorter than 10-20 circulations aren't worth much b/c they do not allow the wells that Miley et al have observed to form. In any case, it's much easier, and almost certainly cheaper, to build a system for microsecond pulses, b/c nanosec pulse widths are a royal pain in the ass to achieve in practice. The commutation time of simple sparkgap is ~50 ns. If your pulse is a few microseconds, you can safely ignore that commutation time. For nanosec pulses, it's a critical factor, and would mean you'd have to shell out for something really expensive, like a hydrogen thryatron.

>Good luck! the 10-6 torr levels will make the ions rather sparse and not allow much current in the device. Large currents, if developed, will really savage the internals of the system too. I hope you get this setup going.

Well, if you are relying exclusively on ionization of ambient neutrals for your fuel ions, then that's true. I see the only way to do it is to pump down to a very high or ultra high vacuum environment, and then inject pre-made plasma. It's going to be a savage environment inside if you go to high power, no matter how you get there.