On the more speculative side, recent research shows that it may be possible to accelerate an electron beam from say 5 mev or 10 mev up to a GEV using a petawatt class laser and wakefield acceleration schemes. I'd like to see a way to produce GEV protons, as these make muons easily, and muons catalyze fusion in certain arrangements.

While the LWFA (Laser Wake Field Accelerator) approach hasn't yet delivered muon capable proton beams, it does seem within reach now that petawatt lasers are reaching the 10s of joules level, and with the recent work, it appears that multistage systems are possible.

THis would potentially enable us to build systems using muons as the "spark" to bootstrap a small fusion power system without the hybrid approaches now necessary. Potentially we could also avoid most of the tritium inventory, and use material systems that would have a minimum of activation over the life of the equipment, vastly reducing the hazardous waste problems that plague present nuclear power systems.

Seems as if we are still a ways off since most research today is driving the basic technology, and applications are quite a ways off. Unfortunately I don't have enough background to know how much energy it takes to produce muons from electrons directly, but I do know it is straightforward given Gev protons, they produce pions, pi- decays into muons, they can be collected.

Who knows, if Dave Jackson is still interested, he's probably already thought of this approach....