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: Pulsed power vs steady state
Date: Apr 22, 7:42 pm
Poster: Jim Lux

On Apr 22, 7:42 pm, Jim Lux wrote:

>Pulsed operation is certainly possible. A pre ionization pulse is not necessary if a steady state ionization voltage is kept across the unit.

Much like a "simmer" supply in the flashlamp business...Current limited, but keeps the ionization going.

Do we even want to keep it ionized though? Won't the HV from the pulse discharge ionize everything quickly enough? Or, perhaps, preionizing makes the rise time of the pulse faster?


Got 'em already in a variety of sizes, including some of the EG&G units (and the triggering electronics too). But why not a triggered spark gap, cheap, fast, etc. The H2 thyratrons are nice for high rep rates, but the standoff voltage isn't all that high, and driving them is a pain.

>The pulsed neutron flux might actually be quite dangerous and rise to huge values. The duration of pulse and rep rate would limit exposure though. The average pulse repitition rate for the thyratrons at full rating are under 1000pps.

Is there any usefulness to high fluxes, even if the average flux is low. For materials modification (transmutation, etc.), I don't think it would matter, total dose is what counts. But, perhaps there are some interesting reactions that are "second tier". Something like 1 out of 10,000 captures creates another ion, which if it also gets hit before it decays, has a 1 in 10,000 chance of creating yet a third which is really interesting. Then, high instantaneous fluxes would be the only way to get the probability of the second reaction occurring up. That is, the interesting reaction would be sort of one of the "critical mass" things, where you need a certain density for it even to run in the first place.

>I have struggled with this idea, but want to consider instrumentation prior to vaulting out on this highway.

No kidding...