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Investigating Laser Preheat and Applied Magnetic Fields Relevant to the MagLIF Fusion Scheme

Harvey-Thompson, Adam J.; Geissel, Matthias G.; Sefkow, Adam B.; Nagayama, Taisuke N.

The MAGnetized Liner Inertial Fusion (MagLIF) scheme has achieved thermonuclear fusion yields on the Z Facility by imploding a cylindrical liner filled with D 2 fuel that is preheated with a multi-kJ laser and pre-magnetized with an axial Bz=10 T magnetic field. Preheating (T e = 100- 200 eV) and pre-magnetizing (10-30 T) the fuel serves to reduce the implosion velocity required to achieve multi-keV fusion-relevant temperatures at stagnation with a modest radial convergence. The challenge of fuel preheat in MagLIF is to deposit multiple-kJ of energy into the underdense (n e /n c %3C0.1) fuel over %7E10 mm target length efficiently and without introducing contaminants. Once the fuel is heated the applied axial magnetic field (o ce t e %7E 10) needs to suppress electron thermal conduction sufficiently to prevent unacceptable heat losses to the liner walls. In this LDRD we investigated laser energy deposition at two facilities: The OMEGA-EP laser at the Laboratory for Laser Energetics and the Z-beamlet laser at Sandia National Labs utilizing the PECOS chamber. Multiple experiments were carried out investigating laser transmission through LEH foils, laser heating of underdense gasses and the effects of magnetization on laser preheat. The studies find that magneto-hydrodynamic simulations are able to reproduce energy deposition at MagLIF-like conditions but that at the intensities currently used to preheat MagLIF significant laser plasma instabilities (LPI) occur which partly explain the inability of codes to reproduce previous MagLIF preheat studies. The experiments find that reducing the intensity and smoothing the beam dramatically reduces the amount of stimulated Brillouin backscatter and produces deposition profiles more similar to those produced in simulations. The experiments have provided a large and varied dataset that can be compared to simulations. As part of the LDRD new experimental capabilities have also been developed that will be used to design future MagLIF integrated experiments and investigate fuel magnetization.

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TYPE SAND Report YEAR 2016
OSTIDOI

Measuring the radiative properties of astrophysical matter using the Z x-ray source

Bailey, James E.; Nagayama, Taisuke N.; Loisel, Guillaume P.; Rochau, G.A.; Blancard, C.B.; Colgan, J.C.; Cosse, Ph.C.; Faussurier, G.F.; Fontes, C.J.F.; Gilleron, F.G.; Golovkin, I.G.; Hansen, Stephanie B.; Iglesias, C.A.I.; Kilcrease, D.P.K.; Macfarlane, Joseph J.; Mancini, Roberto C.; Nahar, S.N.N.; Orban, C.O.; Pain, J.-C.P.; Pradhan, A.K.P.; Sherrill, M.S.; Wilson, B.G.W.

Abstract not provided.

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TYPE Conference Poster YEAR 2016
OSTI

Iron Opacity Measurements at Solar Interior Temperatures

Bailey, James E.; Nagayama, Taisuke N.; Loisel, Guillaume P.; Rochau, G.A.; Blancard, C.B.; Colgan, J.C.; Cosse, Ph.C.; Faussurier, G.F.; Fontes, C.J.F.; Gilleron, F.G.; Golovkin, I.G.; Hansen, Stephanie B.; Iglesias, C.A.I.; Kilcrease, D.P.K.; Macfarlane, Joseph J.; Mancini, Roberto C.; Nahar, S.N.N.; Orban, C.O.; Pain, J.-C.P.; Pradhan, A.K.P.; Sherrill, M.S.; Wilson, B.G.W.

Abstract not provided.

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TYPE Conference Poster YEAR 2016
OSTI

Diagnosing laser-preheated magnetized plasmas relevant to magnetized liner inertial fusion

Physics of Plasmas

Harvey-Thompson, Adam J.; Sefkow, Adam B.; Nagayama, Taisuke N.; Wei, M.S.; Campbell, Edward M.; Fiksel, G.; Chang, P.Y.; Davies, J.R.; Barnak, D.H.; Glebov, V.Y.; Fitzsimmons, P.; Fooks, J.; Blue, B.E.

We present a platform on the OMEGA EP Laser Facility that creates and diagnoses the conditions present during the preheat stage of the MAGnetized Liner Inertial Fusion (MagLIF) concept. Experiments were conducted using 9 kJ of 3ω (355 nm) light to heat an underdense deuterium gas (electron density: 2.5×1020 cm-3=0.025 of critical density) magnetized with a 10 T axial field. Results show that the deuterium plasma reached a peak electron temperature of 670 ± 140 eV, diagnosed using streaked spectroscopy of an argon dopant. The results demonstrate that plasmas relevant to the preheat stage of MagLIF can be produced at multiple laser facilities, thereby enabling more rapid progress in understanding magnetized preheat. Results are compared with magneto-radiation-hydrodynamics simulations, and plans for future experiments are described.

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TYPE Journal Article YEAR 2015
ScopusOSTIDOI

Measuring the opacity of stellar interior matter in terrestrial laboratories

Bailey, James E.; Nagayama, Taisuke N.; Loisel, Guillaume P.; Rochau, G.A.; Blancard, C.B.; Colgan, J.C.; Cosse, Ph.C.; Faussurier, G.F.; Fontes, C.J.F.; Gilleron, F.G.; Golovkin, I.G.; Hansen, Stephanie B.; Iglesias, C.A.I.; Kilcrease, D.P.K.; Macfarlane, Joseph J.; Mancini, Roberto C.; Nahar, S.N.N.; Orban, C.O.; Pain, J.-C.P.; Pradhan, A.K.P.; Sherrill, M.S.; Wilson, B.G.W.

Abstract not provided.

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TYPE Presentation YEAR 2015
OSTI

Iron Opacity Measurements at Solar Interior Temperatures

Bailey, James E.; Nagayama, Taisuke N.; Loisel, Guillaume P.; Rochau, G.A.; Blancard, C.B.; Colgan, J.C.; Cosse, Ph.C.; Faussurier, G.F.; Fontes, C.J.F.; Gilleron, F.G.; Golovkin, I.G.; Hansen, Stephanie B.; Iglesias, C.A.I.; Kilcrease, D.P.K.; Macfarlane, Joseph J.; Mancini, Roberto C.; Nahar, S.N.N.; Orban, C.O.; Pain, J.-C.P.; Pradhan, A.K.P.; Sherrill, M.S.; Wilson, B.G.W.

Abstract not provided.

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TYPE Conference Poster YEAR 2015
OSTI
Results 76–100 of 127
Results 76–100 of 127