The potential benefits of a fusion power system are great, though it seems likely that we will see hybrid fusion-fission systems first, and they have safety considerations that are serious. Yet with greenhouse warming fast becomming the most important threat to humanity, developing options independent of fossil fuels is vital. Accordingly, the fusion technology programs that have been put on hold or scaled down should instead be ramped up, and we ought to divert a billion or so from the Iraq War to push fast ignition research, z-pinch, and applications development.

In the U.S. the environmental movement hasn't yet incorporated the new logic of combating global warming, a new logic that will drive some policy shifts, require some new thinking from the leaders if they are to remain relevant.

We must also develop the renewable energy systems, but it's too early to rule out the fusion option just because there are some thorny operational safety issues. Tritium handling comes into play in most fusion cycle plants, and tritium is tricky to handle. Tritium safety is a topic that has been studied and practiced for decades, so there is quite a large body of knowledge to work with. These plants will introduce some new chemical hazards, pressure regimes not seen before such as the cycling as pellets are "burned", liquid lithium blankets, and the need to control the proliferation potential at plant sites.

Never the less, these systems can also breed fuel for the existing fission cycle plants, or better, for third generation fission cycle plants using sub critical assemblies that are only driven to criticality by the fusion burns. The inherrent citicality safety of such power plants was the topic of a talk by a nobel prize winning CERN scientist some years ago at UC Berkeley. He advocated thorium fission power, using a 55 gallon drum sized "core" assembly along with an accelerator beam that brought it to the power production level.

These fusion neutrons are mostly 17 kev to start, definately "fast" neutrons ---- :-)

Following this draft, I came on a very recent paper in Phisics Letters "A" by F. Winterberg that talks about hybrid fusion-fission-fusion using his favorite device, the dense plasma focus....of course. FW has a distaste for lasers, seems to go a bit light on the math in his paper, nevertheless, it confirms my post above ( drafted prior to his article being published), and does give some idea of the design. Clearly with a bit of extrapolation, my idea of a laser initiated DPF system would also go, and likely with less tricky stuff than FW's system. He doesn't get much of a following by the folks with the money for some reason, but his papers point at a simple way to get lots of neutrons.

Combine his approach with the Carlos Rubbia ideas, and it's clear that one could bootstrap with just a bit of laser created dt fuel into a full fuel cycle.

interesting.

Recent news from Osaka, Japan published by the scientists and engineers at ILE states that they now are confident that fast ignition of a fusion burn by a petawatt laser coupled with the existing multibeam laser compression systems "is understood".

Simple in concept, the system is capable of taking a plastic pellet containing dt and once compressed by the main lasers, hits it with a petawatt pulse that generates a burst of high energy electrons and ions that interacts with the compressed pellet and initiates fusion reactions.

The exciting thing reported by the researchers is that when they tried this experiment, when they synchronized the petawatt beam with maximum compression, they generated a burst of neutrons indicating that the petawatt beam does indeed boost the compressed target into the fusion regime.

One would think that our government would at least want to keep the US in the forefront of such potentially world order changing research, but the reality is that our effort has been cut back, the money throttled down, and thus the U.S. isn't moving as fast as possible to understand and ultimately to exploit this new technology.

One thing that governments don't always consider is that this generation of scientists has a limited time working at maximum productivity before the biological limitations set in. It takes so many years to master the math, physics, technology and so on that unless we really push them once they start to be scientifically productive, we don't get the full benefit of their intuition.

When the experiments take years to develop on machines that cost billions, the limitations are both "understandable" and stupid. This technology has the potential to help with shifting energy production away from greenhouse producing fossil fuels, to enable us to develop new space propulsion systems capable of vastly improving our planetary exploration, using simple materials plentiful on earth. This technology could also extend the life of our conventional fission power systems by hundreds of years.

Since our civilization has only a limited time to develop energy sources that don't screw-up the environment on a global scale, it is important to push this "fast igniter" effort as fast as possible.
I hope that we can perhaps find someone in a position to nudge the budget folks to enable the US to help the worldwide effort to bring this idea to blossom. It might be the most important tiny nudge in resources possible at this time.