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This paper in PRL suggests that a compact accelerator can generate electrons with enough energy to produce muons. While the device described below wasn't configured to produce secondary particles in a controlled manner, this paper shows that the energy regime needed to generate muons is accessible with currently available technology.

The accelerator described was less than 2cm long, and is actually a device created in an instant by the use of a burst of laser energy on a target, an ephemeral device that I speculate could be used as below with a bit more development. Such a device could be designed to operate in the reaction chamber of a FireEx or NIF machine.

Self-Guided Laser Wakefield Acceleration beyond 1 GeV Using Ionization-Induced Injection

C. E. Clayton1,*, J. E. Ralph2, F. Albert2, R. A. Fonseca3, S. H. Glenzer2, C. Joshi1, W. Lu1, K. A. Marsh1, S. F. Martins3, W. B. Mori1, A. Pak1, F. S. Tsung1, B. B. Pollock2,4, J. S. Ross2,4, L. O. Silva3, and D. H. Froula2

URL:
http://link.aps.org/doi/10.1103/PhysRevLett.105.105003

DOI:
10.1103/PhysRevLett.105.105003

PACS:
52.38.Kd, 41.75.Jv, 52.35.Mw

One could then envision a "second generation" fast ignition scenario, where one uses muons instead of fast electrons to create the "spark" that ignites the compressed dt fuel capsule. In a second generation system, the "spark" is created using muons to catalyze fusion in a volumetric manner, yielding what would look like an isochoros type heating of the mix to ignition conditions. The muon can catalyze as many as 150 fusion events before it sticks, producing a sharp spike in heat as both the fusion energy is released and as the fusion byproducts are absorbed in the dense capsule core. Understanding and modeling the stopping dynamics of muons producing muon-catylized fusion in a capsule context is beyond the current scope but would be interesting to explore. Muon-catylized fusion seemed to work best on cold mixtures, if my memory serves( I think that some of the papers from the Swiss lab and from Los Alamos a while back discussed these curves both from an experimental point of view, and from a theoretical point of view).

These experiments could be performed at the NIF experimental hall if the auxiliary laser beamline could be constructed without disturbing the ongoing experimental campaign. Naturally one would want to do careful simulation of various device configurations to explore how to arrange the materials, the layers, and the timing so that it could be effective during a compression event with the main beamlines.

This idea is more likely to work with a z-pinch device as it can have magnetic bottles with axial symmetry and a long enough bottle to absorb the bulk of the muons. One trick is to understand how muons would navigate the complicated magnetic and matter fields on the way to the target from their origin. Since high energy muons can penetrate quite a distance, this could mean that they would go right past any capsule that you were hoping would catch the precious muons.......With understanding one would hope to cool the muons to the point where they just "get there" with enough energy to have the catalytic interaction with the DT pair for fusion to occur in a resonant event.

Pretty far fetched, but then, it wasn't even possible to envision such a system at all just a few years ago! Muon producing accelerators were huge, luminosity low, and dealing with muons (mu-) difficult.

It seems more likely to me that with super intense lasers, the acceleration of beams of protons or better yet, heavy ions will make a more practical fusion igniter. Beams of protons have already been produced. These tiny proton accelerators can be set so that they are opposed on either side of the Holeraum so that the intersecting beams meet at the center of the compressed target. We are taking advantage of the bragg peak to ensure that the maximum energy disposition occurs in the target. This multiplies the energy delivered as a spark, all that is needed if the compression is sufficient to shorten the stopping distance for the reaction byproducts to within the capsule central zone.

Tricky experimental environment, as these things tend to evaporate if they work, and it's challenging to design optics that don't get messed up every time you do an experiment. If it works the whole thing is history in a few times 10e-10 seconds.

In the case of the z pinch, the ion thing is also more likely to be practical than the muon approach. but the muon approach is interesting for other reasons.

Both are worth investigation.

See here:

APS » Journals » Phys. Rev. Lett. » Volume 105 » Issue 10

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Phys. Rev. Lett. 105, 105003 (2010) [4 pages]
Self-Guided Laser Wakefield Acceleration beyond 1 GeV Using Ionization-Induced Injection
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C. E. Clayton1,*, J. E. Ralph2, F. Albert2, R. A. Fonseca3, S. H. Glenzer2, C. Joshi1, W. Lu1, K. A. Marsh1, S. F. Martins3, W. B. Mori1, A. Pak1, F. S. Tsung1, B. B. Pollock2,4, J. S. Ross2,4, L. O. Silva3, and D. H. Froula2
1Department of Electrical Engineering, University of California, Los Angeles, California 90095, USA
2L-399, Lawrence Livermore National Laboratory, P.O. Box 808, Livermore, California 94551, USA
3GoLP/IPFN-LA, Instituto Superior Técnico, Lisboa, Portugal
4MAE Department, University of California, San Diego, La Jolla, California 92093, USA

Received 23 April 2010; published 1 September 2010

The concepts of matched-beam, self-guided laser propagation and ionization-induced injection have been combined to accelerate electrons up to 1.45 GeV energy in a laser wakefield accelerator. From the spatial and spectral content of the laser light exiting the plasma, we infer that the 60 fs, 110 TW laser pulse is guided and excites a wake over the entire 1.3 cm length of the gas cell at densities below 1.5×1018  cm-3. High-energy electrons are observed only when small (3%) amounts of CO2 gas are added to the He gas. Computer simulations confirm that it is the K-shell electrons of oxygen that are ionized and injected into the wake and accelerated to beyond 1 GeV energy.

© 2010 The American Physical Society
URL:
http://link.aps.org/doi/10.1103/PhysRevLett.105.105003
DOI:
10.1103/PhysRevLett.105.105003
PACS:
52.38.Kd, 41.75.Jv, 52.35.Mw

*cclayton@ucla.edu