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ABSTRACT: Integrated magnetic modeling and design are important to meet the requirements for (1) formation, (2) translation, and (3) compression of a field reversed configuration (FRC) for magnetized target fusion. Off-the-shelf solutions do not exist for many generic design issues. A predictive capability for time-dependent magnetic diffusion in realistically complicated geometry is essential in designing the experiment. An eddy-current code was developed and used to compute the mutual inductances between driven magnetic coils and passive magnetic shields (flux excluder plates) to calculate the self-consistent axisymmetric magnetic fields during the first two stages. The plasma in the formation stage was modeled as an immobile solid cylinder with selectable constant resistivity and magnetic flux that was free to readjust itself. It was concluded that (1) use of experimentally obtained anomalously large plasma resistivity in magnetic diffusion simulations is sufficient to predict magnetic reconnection and FRC formation, (2) comparison of predicted and experimentally observed timescales for FRC Ohmic decay shows good agreement, and (3) for the typical range of resistivities, the magnetic null radius decay rate scales linearly with resistivity. The last result can be used to predict the rate of change in magnetic flux outside of the separatrix (equal to the back-emf loop voltage), and thus estimate a minimum θ -coil loop voltage required to form an FRC.
Journal of Applied Physics 11/2008; · 2.17 Impact Factor
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R.E. Siemon,
W.L. Atchison, T. Awe,
B.S. Bauer,
A.M. Buyko,
V.K. Chernyshev,
T.E. Cowan,
J.H. Degnan,
R.J. Faehl,
S. Fuelling, [......],
T. Goodrich,
A.V. Ivanovsky,
I.R. Lindemuth,
V. Makhin,
V.N. Mokhov,
R.E. Reinovsky,
D.D. Ryutov,
D.W. Scudder,
T. Taylor,
V.B. Yakubov
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ABSTRACT: In the 'metal liner' approach to magnetized target fusion (MTF), a preheated magnetized plasma target is compressed to thermonuclear temperature and high density by externally driving the implosion of a flux conserving metal enclosure, or liner, which contains the plasma target. As in inertial confinement fusion, the principal fusion fuel heating mechanism is pdV work by the imploding enclosure, called a pusher in ICF. One possible MTF target, the hard-core diffuse z pinch, has been studied in MAGO experiments at VNIIEF and is one possible target being considered for experiments on the Atlas pulsed power facility. Numerical MHD simulations show two intriguing and helpful features of the diffuse z pinch with respect to compressional heating. First, in two-dimensional simulations the m = 0 interchange modes, arising from an unstable pressure profile, result in turbulent motions and self-organization into a stable pressure profile. The turbulence also gives rise to convective thermal transport, but the level of turbulence saturates at a finite level, and simulations show substantial heating during liner compression despite the turbulence. The second helpful feature is that pressure profile evolution during compression tends towards improved stability rather than instability when analysed according to the Kadomtsev criteria. A liner experiment is planned for Atlas to study compression of magnetic flux without plasma, as a first step. The Atlas geometry is compatible with a diffuse z pinch, and simulations of possible future experiments show that kiloelectronvolt temperatures and useful neutron production for diagnostic purposes should be possible if a suitable plasma injector is added to the Atlas facility.
Nuclear Fusion 08/2005; 45(9):1148. · 4.09 Impact Factor
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IEEE Conference Record - Abstracts. 2005 IEEE International Conference on Plasma Science - ICOPS 2005 (IEEE Cat No. 05CH37707).
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T. P. Intrator,
G. A. Wurden,
W. J. Waganaar,
R. Renneke,
M. Kostora,
L. Dorf,
S. C. Hsu,
A. Lynn,
M. Gilmore,
R. Siemon, T. Awe,
J. Degnan,
C. Grabowski,
E. Ruden
AIP Conference Proceedings. 1154.
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T. P. Intrator,
G. A. Wurden,
P. E. Sieck,
W. J. Waganaar,
L. Dorf,
M. Kostora,
R. J. Cortez,
J. H. Degnan,
E. L. Ruden,
M. Domonkos, [......],
D. G. Gale,
W. Sommars,
M. Frese,
S. Frese,
J. F. Camacho,
P. Parks,
R. E. Siemon, T. Awe,
A. G. Lynn,
R. Gribble
Journal of Fusion Energy. 28(2):165-169.
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T. P. Intrator,
G. A. Wurden,
W. J. Waganaar,
R. Renneke,
M. Kostora,
L. Dorf,
S. C. Hsu,
A. Lynn,
M. Gilmore,
R. Siemon, T. Awe,
J. Degnan,
C. Grabowski,
E. Ruden
Current Trends in International Fusion Research, Proceedings. 1154:65-67.
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T. P. Intrator,
G. A. Wurden,
P. E. Sieck,
W. J. Waganaar,
R. Renneke,
L. Dorf,
M. Kostora,
S. C. Hsu,
A. G. Lynn,
M. Gilmore,
R. E. Siemon, T. Awe,
J. Degnan,
C. Grabowski,
E. L. Ruden
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ABSTRACT: We describe a physics scaling model used to design the high density field reversed configuration (FRC) at LANL that will translate into a mirror bounded compression region, and undergo Magnetized Target Fusion compression to a high energy density plasma. At Kirtland AFRL the FRC will be compressed inside a flux conserving cylindrical shell. The theta pinch formed FRC will be expelled from inside a conical theta coil. Even though the ideal FRC has zero helicity and toroidal magnetic field, significant non-ideal properties follow from formation within a conical (not cylindrical) theta coil. The FRC stability and lifetime properties may improve. Several experimental features will also allow unique scientific investigations of this high Lundquist number but collisional plasma.
Journal of Fusion Energy. 27(1-2):57-60.
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A. G. Lynn,
T. P. Intrator,
W. J. Waganaar,
E. L. Ruden,
C. Grabowski,
G. A. Wurden,
J. H. Degnan,
M. Domonkos,
P. Adamson,
D. G. Gale, [......],
D. J. Amdahl,
P. Parks, T. Awe,
P. E. Sieck,
X. Sun,
S. D. Frese,
J. F. Camacho,
N. F. Roderick,
R. E. Siemon,
M. Gilmore
2009 IEEE 36th International Conference on Plasma Science (ICOPS).
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T. P. Intrator,
G. A. Wurden,
W. J. Waganaar,
P. E. Sieck,
R. Oberto,
T. D. Olson,
D. Sutherland,
J. H. Degnan,
E. L. Ruden,
M. Domonkos, [......],
M. H. Frese,
S. D. Frese,
J. F. Camacho,
S. K. Coffey,
N. F. Roderick,
D. J. Amdahl,
P. Parks,
R. E. Siemon, T. Awe,
A. G. Lynn
2010 IEEE 37th International Conference on Plasma Sciences (ICOPS 2010).
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G A Wurden,
T P Intrator,
R Renneke,
S Y Zhang,
L A Dorf,
S C Hsu,
J Y Park,
W J Waganaar,
R E Siemon, T Awe,
A G Lynn,
M Gilmore,
J H Degnan,
D G Gale,
C Grabowski,
E L Ruden,
W Sommars
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ABSTRACT: We are developing a field reversed configuration (FRC) plasma for application as the target plasma to demonstrate the physics of magnetized target fusion (MTF) [1]. The FRX-L experiment at Los Alamos has the goal of demonstrating plasma parameters good enough to warrant moving toward translation and implosion experiments [2,3]. The FRC experimental parameters (density, temperature, and cleanliness) obtained in the past several years are sufficient, but we still have two remaining issues. These are: a relatively short lifetime ~10 µsec, and low probability (~10%) of forming an FRC that would remain static, centered around the central region Θ-coils, where our primary diagnostics are located. Consequently, the focus of our recent experimental campaigns has been to enhance performance in these two areas, which has resulted in the following accomplishments: • improved reproducibility of good FRC's via PI/main bank timing experiments • improved FRC performance due to upgraded crowbar switch which has minimized magnetic field ringing and premature deterioration of FRC's • increased n e , <T e +T i >, & plasma pressure, including 0.7 mWb trapped flux during formation • modeled time-dependent cusps and field penetration of flux-excluder plates to optimize formation and flux trapping, designed add-on mirror coils, and are using an analytic model and MOQUI simulations [4] to design the FRC translation experiment Figure 1: High pressure FRC parameters in FRX-L, following installation of improved high-current crowbar system. The plasma pressure is 2-3 MegaPascals, or 20-30 bars; higher than even the largest tokamak plasmas. An n=2 rotational instability develops by t=20 µsec.
