Magnetized Liner Inertial Fusion & Cylindrical Dynamic Materials Properties Experiments on the Z Pulsed-Power Accelerator

Ryan McBride, Sandia National Laboratories, New Mexico

Magnetized Liner Inertial Fusion (MagLIF) [1,2] is an exciting new concept that involves using a pulsed electrical current to implode an initially solid, cylindrical metal tube (liner) filled with preheated and premagnetized fusion fuel (deuterium or deuterium-tritium). This fast z-pinch implosion results from magnetic field pressure operating on the liner’s outer surface, thus driving the liner radially inward. One- and two-dimensional simulations predict that if sufficient liner integrity can be maintained throughout the implosion, then significant fusion yield (>100 kJ with deuterium-tritium fuel) is possible on the 27-MA, 100-ns Z pulsed-power accelerator at Sandia National Laboratories. These yields are interesting because they exceed the energy delivered to the fuel, a threshold often referred to as “scientific breakeven”, which has yet to be obtained in a controlled fashion in the laboratory.

At Sandia, we are presently designing new MagLIF experiments with 1D, 2D, and 3D radiation-magnetohydrodynamics (rad-MHD) simulation codes, as well as working to integrate the new premagnetization and laser preheating capabilities into the Z facility.  Once completed, we will begin preliminary tests of the fully integrated MagLIF concept, hopefully by the end of calendar year 2013.  These first tests will be at premagnetization, preheat, and drive current levels that are below that required for the MagLIF point design [1], but that will nevertheless provide insight into the physics of the MagLIF concept.

This talk will present an introduction to the physics of MagLIF as well as experimental progress to date.  The experimental results are from radiographed liner implosion experiments designed to study the development of the magneto-Rayleigh-Taylor [3-6] and electro-thermal [7,8] instabilities. We will show how the understandings that we have gained from these experiments are now allowing us to mitigate some of the deleterious effects of these instabilities.  We will also present results from our first premagnetization experiments, where we found that the premagnetization markedly altered the instability structure that develops on the liner’s outer surface, changing it from primarily azimuthally symmetric structure to primarily helical structure.  Finally, we will present experiments that used the MagLIF experimental platform to investigate the benefits of equation-of-state measurements in a cylindrically convergent geometry (as opposed to a planar/divergent geometry), where higher material pressures and densities can be obtained for measurements on and off of a material’s shock Hugoniot [6,9]. So far these techniques have allowed us to extend the experimentally inferred isentrope of beryllium out to densities and pressures of about 5 g/c3 and 5.5 Mbar, respectively [9]. Throughout this talk, comparisons to 2D and 3D rad-MHD simulations will also be presented.

[1] S. A. Slutz et al., Phys. Plasmas 17, 056303 (2010).

[2] S. A. Slutz and R. A. Vesey, Phys. Rev. Lett. 108, 025003 (2012).

[3] D. B. Sinars et al., Phys. Rev. Lett. 105, 185001 (2010).

[4] D. B. Sinars et al., Phys. Plasmas 18, 056301 (2011).

[5] R. D. McBride et al., Phys. Rev. Lett. 109, 135004 (2012).

[6] R. D. McBride et al., Phys. Plasmas 20, 056309 (2013).

[7] K. J. Peterson et al., Phys. Plasmas 19, 092701 (2012).

[8] K. J. Peterson et al., Phys. Plasmas 20, 056305 (2013).

[9] M. R. Martin et al., Phys. Plasmas 19, 056310 (2012).

This work was conducted in collaboration with S. A. Slutz, C. A. Jennings, T. J. Awe, D. B. Sinars, M. E. Cuneo, K. J. Peterson, M. C. Herrmann, R. W. Lemke, M. R. Martin, C. W. Nakhleh, D. C. Rovang, B. E. Blue, J. B. Greenly, D. D. Ryutov et al., and the Z & ZBL operations, diagnostics, engineering, load hardware, and target teams. This work was funded in part by Sandia’s LDRD program. Sandia National Laboratories is a multi-program laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corporation, for the U.S. Department of Energy's National Nuclear Security Administration under contract DE-AC04-94AL85000.

Abstract Author(s): Ryan D. McBride