Publications

Demonstration of thermonuclear conditions in magnetized liner inertial fusion experiments

Gomez, Matthew R.; Slutz, S.A.; Sefkow, Adam B.; Hahn, K.D.; Hansen, Stephanie B.; Knapp, P.F.; Schmit, Paul S.; Ruiz, Carlos L.; Sinars, Daniel S.; Harding, Eric H.; Jennings, C.A.; Awe, T.J.; Geissel, Matthias G.; Rovang, Dean C.; Smith, Ian C.; Chandler, Gordon A.; Cooper, Gary W.; Cuneo, M.E.; Harvey-Thompson, Adam J.; Herrmann, M.C.; Hess, Mark H.; Lamppa, Derek C.; Martin, M.R.; McBride, Ryan D.; Peterson, Kyle J.; Porter, John L.; Rochau, G.A.; Savage, Mark E.; Schroen, D.G.; Stygar, William A.; Vesey, Roger A.

The magnetized liner inertial fusion concept [S. A. Slutz et al., Phys. Plasmas 17, 056303 (2010)] utilizes a magnetic field and laser heating to relax the pressure requirements of inertial confinement fusion. The first experiments to test the concept [M. R. Gomez et al., Phys. Rev. Lett. 113, 155003 (2014)] were conducted utilizing the 19 MA, 100-ns Z machine, the 2.5-kJ, 1 TW Z Beamlet laser, and the 10-T Applied B-field on Z system. Despite an estimated implosion velocity of only 70-km/s in these experiments, electron and ion temperatures at stagnation were as high as 3-keV, and thermonuclear deuterium-deuterium neutron yields up to 2-×-10¹² have been produced. X-ray emission from the fuel at stagnation had widths ranging from 50 to 110 μm over a roughly 80% of the axial extent of the target (6-8-mm) and lasted approximately 2-ns. X-ray yields from these experiments are consistent with a stagnation density of the hot fuel equal to 0.2-0.4-g/cm³. In these experiments, up to 5-×-10¹⁰ secondary deuterium-tritium neutrons were produced. Given that the areal density of the plasma was approximately 1-2-mg/cm², this indicates the stagnation plasma was significantly magnetized, which is consistent with the anisotropy observed in the deuterium-tritium neutron spectra. Control experiments where the laser and/or magnetic field were not utilized failed to produce stagnation temperatures greater than 1-keV and primary deuterium-deuterium yields greater than 10¹⁰. An additional control experiment where the fuel contained a sufficient dopant fraction to substantially increase radiative losses also failed to produce a relevant stagnation temperature. The results of these experiments are consistent with a thermonuclear neutron source.