Bussard Fusion Discussion

There is a very interesting on going discussion of the Bussard Fusion Reactor at NASA Space Flight Forums. I'm going to excerpt some choice bits but if you are nerdy like me you will want to read the whole thing. Here is a bit from Dr. Bussard explaining why funding is hard to come by.

As for energy companies "stampeding" to support us -- It is clear that a view like this is ignorant of the reality of energy companies. There is only one thing the oil cvompanies want, and that is to sell oil, and more oil. So long as the fields pump, the oil companies will squeeze. They have NO, absolutely NO interest in anything new, ins spite of all their foolish ads in magazines for wind mills and solar-PV roofs. It is all just show and tell. I know these guys, and there is no way they would support anything that might get in the way of oil. The only way to stop oil, from their view, is when it does run out. And then they''ll go for deeper drilling, new fields, Gulf geopressure gas, LNG, etc, etc, and keep raising the price, until finally foolish solar and windmills become competitive.

Tom Ligon gets technical:

At one point in his paper, Rider seemed to make the assumption that the machine would maxwellianize because all plasmas maxwellianize. That's how plasmas are usually taught. But a properly designed IEC machine has a very non-maxwellian energy distribution, and ions reaching the center are nearly mono-energetic. IEC machines are particle accelerators, not heat machines. The only place where a properly-run machine maxwellianizes is close to the inner surface of the MaGrid, where the ions slow down and turn around for another pass. At that point, the density is high and they actually do maxwellianize ... and in the process equalize out any kinetic energy imbalances they developed due to collisions at higher energies. Rider raised the objection that the high energy non-fusion collisions would result in maxwellianization, and the machine itself responded by using maxwellianization to fix the problem!

The whole key is finding a density low enough to allow decent mean free paths for the ions when transitioning most of the radius of the machine, but still high enough that fusion is likely in the high-density central focus region. Done right, you find this sweet spot, which is not unlike finding the right fuel/air ratio to make an internal combustion engine run.

Maxwellianize means that the plasma would have the energies of its particles thermally distributed. That means few at high energies most at a lower energy peak and almost none with zero energy. It would look like this. As the temperature rises the peak flattens and the peak also moves to a higher velocity. You don't see this effect in the Bussard reactor because it is in effect a linear accelerator and the atoms and electrons are not in any kind of thermal equilbrium. They are constantly exchanging energy with the electric field as they move in and out of the reaction volume.

There is lots more including lots on space flight possibilities and more on Dr. Bussard's funding problems.

To view the thread with posting options go here.