High-Gain Magnetized Inertial Fusion
Stephen A. Slutz · Roger A. Vesey
Abstract and summary · read the original at the source · none found
In one page
Stephen Slutz and Roger Vesey, at Sandia National Laboratories, take the fusion scheme built around Sandia’s Z machine and show in simulation how it could reach the yields an actual power plant needs. The scheme, magnetized liner inertial fusion, wraps deuterium-tritium fuel in a metal cylinder, magnetizes it, warms it with a laser and then crushes the cylinder with a huge pulse of current. Magnetizing the fuel holds the heat in and keeps the fast helium nuclei from escaping, which is what makes ignition reachable at a gentle squeeze. The new ingredient here is a layer of frozen deuterium-tritium ice lining the inside of the cylinder. The simulations show a burn wave leaving the hot centre and eating outward into that cold dense ice, provided the hot spot is dense enough to start it. At a drive current of 60 million amps the simulated energy gain passes 100, and at 70 million amps it passes 1000.
Why it matters hereChapter 12 treats fusion as the near-term door the vacuum programme opens onto, and this paper is the design study that puts a number on it: a pulsed-power machine of the kind Sandia already runs, plus a ring of deuterium-tritium ice, returning a hundred times the energy the liner absorbs. Gain here is a fuel-burning reactor returning more than it draws, which is a separate question from drawing energy from the vacuum.
What it claims
01Magnetizing the fuel substantially eases the plasma conditions needed for significant fusion yield, which is what makes ignition reachable with the slow implosion and modest radial squeeze a cylindrical liner gives you — the point of the magnetized liner inertial fusion concept the authors published in Physics of Plasmas 17, 056303 in 2010.Abstract, first two sentences
On the bench now02Adding a cryogenic layer of deuterium-tritium ice inside the liner turns the scheme from a batch burn into a propagating one: the simulations show a burn wave moving radially out of the magnetized hot spot into the surrounding much denser cold fuel, provided the hot spot reaches sufficient areal density.Abstract, third and fourth sentences
Published and peer-reviewed03For a drive current of 60 million amps the simulated gain exceeds 100, which the authors state is more than adequate for fusion energy applications, and for 70 million amps the simulated gain exceeds 1000.Abstract, final two sentences
Published and peer-reviewed04The magnetic field is a two-sided knob and there is an optimum: inhibiting radial heat conduction and holding the alpha particles in lowers the hot-spot areal density needed for ignition, while too strong a field slows the burn wave moving into the cold fuel — so the high-gain design lowers the initial axial field to about 10 tesla, where the gas-only design used about 30.Authors’ companion Sandia presentation SAND2011-5344C, radial-propagation slides and summary slide
Designed, not yet built05The cost of the extra ice layer is modest: the laser preheat energy rises to roughly 22 kilojoules, and the authors’ own gain threshold for inertial fusion energy — set by the electricity conversion efficiency, the recirculated power fraction and the driver efficiency of a magnetic implosion — is a gain of about 50, which the simulated designs clear by a wide margin.Authors’ companion Sandia presentation SAND2011-5344C, high-gain requirement and summary slides
Designed, not yet built06The measurement that would settle the design is the instability behaviour of the liner surface: two-dimensional simulations say short-wavelength magneto-Rayleigh-Taylor growth is the most damaging feature and that root-mean-square surface roughness of less than about 20 nanometres may be required, and the authors call for three-dimensional simulation and further experiment to fix the real tolerance.Authors’ companion Sandia presentation SAND2011-5344C, magneto-Rayleigh-Taylor slides and summary slide
What to watch
Read it · abstract
Abstract
Magnetized inertial fusion (MIF) could substantially ease the difficulty of reaching plasma conditions required for significant fusion yields, but it has been widely accepted that the gain is not sufficient for fusion energy. Numerical simulations are presented showing that high-gain MIF is possible in cylindrical liner implosions based on the MagLIF concept [S. A. Slutz et al., Phys. Plasmas 17, 056303 (2010)] with the addition of a cryogenic layer of deuterium-tritium (DT). These simulations show that a burn wave propagates radially from the magnetized hot spot into the surrounding much denser cold DT given sufficient hot-spot areal density. For a drive current of 60 MA the simulated gain exceeds 100, which is more than adequate for fusion energy applications. The simulated gain exceeds 1000 for a drive current of 70 MA.
The way in
https://doi.org/10.1103/PhysRevLett.108.025003Published as Physical Review Letters 108, 025003, on 12 January 2012, by Stephen A. Slutz and Roger A. Vesey of Sandia National Laboratories. Licence checked directly: the article carries the APS default licence and the accepted manuscript released through CHORUS carries the APS accepted-manuscript licence, neither of which is a Creative Commons grant, and the Department of Energy record at OSTI, biblio 1098940, is a citation without full text. So this sheet carries the summary, the claims and the published abstract, and sends the reader to the source. The abstract below is the published one, read from the article record itself. The version of record is behind a subscription; claims about simulation parameters are located against the authors’ own publicly released Sandia presentation of the same work, High-Gain Magnetized Liner Inertial Fusion, SAND2011-5344C, given at DZP Biarritz in June 2011 and available in full from OSTI as record 1106530, and each such claim says so. Registry correction: the fetched metadata listed Matthew R. Gomez among the creators of this paper; the authors of Physical Review Letters 108, 025003 are Slutz and Vesey, and Gomez is an author on the later MagLIF experimental results.
How to cite it
Stephen A. Slutz, Roger A. Vesey (2012) High-Gain Magnetized Inertial Fusion. doi:10.1103/PhysRevLett.108.025003
Where it sits in the curriculum