Magnetized Target Fusion

Irvin R. Lindemuth, University of Nevada, Reno

February 10, 2016, 1:00 - 2:00pm, SERF 329

Abstract:  Magnetized target fusion (MTF) is an emerging third pathway to controlled fusion energy research. MTF (aka Magneto- Inertial Fusion) addresses the question “is there anything in between” the 11 orders of magnitude (a factor of 1011) in density that separates the two conventional approaches, magnetic confinement fusion (MCF), as exemplified by ITER, and the density of inertial confinement fusion (ICF), as exemplified by the National Ignition Facility (NIF). MTF combines ICF’s implosion heating method with MCF’s use of a magnetic field to reduce thermal conduction energy losses. MTF is a two-step process: (a) formation of a warm, magnetized plasma, similar to MCF but with important differences; (b) compression of the plasma to fusion temperatures by an imploding, higher density shell, i.e., pusher or liner, similar to ICF but with important differences. When compared with MCF, MTF requires orders of magnitude less fuel mass and hence less energy. When compared with ICF, MTF requires orders of magnitude less compressional heating power, and hence lower velocity than ICF’s difficult-to-achieve 40 cm/s. In addition MTF has the possibility of reaching fusion temperature at a significantly lower radial convergence (ratio of initial radius to final radius) than ICF’s difficult to achieve 35-40. Although the possible advantage of magnetized fuel in a fusion target has been recognized for more than five decades, recent theoretical, computational and experimental advances have increased international interest in MTF. A recent $30M program announced by the US Department of Energy Advanced Research Projects Agency (ARPA-E) “will focus on intermediate density fusion approaches between low-density, magnetically confined plasmas and high-density, inertially confined plasma” and offers hope of forming an MTF “critical mass” so that MTF may reach a level of technical maturity. This presentation discusses some of MTF’s history and reviews a recent paper (Phys. Plas. 22, 122712, December 2015) that delineated the parameter space in which MTF might achieve ignition and high gain. The results can be used to guide MTF plasma formation research and driver development.

Bio:  Dr. Lindemuth retired from full-time employment in November, 2003 after more than 32 years at the University of California, first at the Lawrence Livermore National Laboratory and then at the Los Alamos National Laboratory. Prior to joining Los Alamos in 1978, he was a technical staff member in A-Division at the Lawrence Livermore National Laboratory where he was involved in fusion research. Dr. Lindemuth received his B.S. degree in Electrical Engineering from Lehigh University in 1965 and his M.S. and Ph.D. degrees in Engineering—Applied Science from the University of California, Davis/Livermore in 1967 and 1971, respectively. Dr. Lindemuth currently resides in Tucson, Arizona and is an Adjunct Professor in the Physics Department at the University of Nevada, Reno.