NIMROD Resistive Magnetohydrodynamic Simulations of Spheromak Physics

Journal Article · Tue Dec 11 04:00:00 EST 2007 · Physics of Plasmas

OSTI ID:941397

Hooper, E B; Cohen, B I; McLean, H S; Wood, R D; Romero-Talamas, C A; Sovinec, C R

The physics of spheromak plasmas is addressed by time-dependent, three-dimensional, resistive magneto-hydrodynamic simulations with the NIMROD code. Included in some detail are the formation of a spheromak driven electrostatically by a coaxial plasma gun with a flux-conserver geometry and power systems that accurately model the Sustained Spheromak Physics Experiment (SSPX) (R. D. Wood, et al., Nucl. Fusion 45, 1582 (2005)). The controlled decay of the spheromak plasma over several milliseconds is also modeled as the programmable current and voltage relax, resulting in simulations of entire experimental pulses. Reconnection phenomena and the effects of current profile evolution on the growth of symmetry-breaking toroidal modes are diagnosed; these in turn affect the quality of magnetic surfaces and the energy confinement. The sensitivity of the simulation results address variations in both physical and numerical parameters, including spatial resolution. There are significant points of agreement between the simulations and the observed experimental behavior, e.g., in the evolution of the magnetics and the sensitivity of the energy confinement to the presence of symmetry-breaking magnetic fluctuations.

• Research Organization: Lawrence Livermore National Laboratory (LLNL), Livermore, CA
• Sponsoring Organization: USDOE
• DOE Contract Number: W-7405-ENG-48
• OSTI ID: 941397
• Report Number(s): UCRL-JRNL-237225
• Journal Information: Physics of Plasmas, Journal Name: Physics of Plasmas Journal Issue: 3 Vol. 15; ISSN PHPAEN; ISSN 1070-664X
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
CONFINEMENT
DECAY
FLUCTUATIONS
GEOMETRY
MAGNETIC SURFACES
MAGNETOHYDRODYNAMICS
NIMROD
PHYSICS
PLASMA GUNS
POWER SYSTEMS
SENSITIVITY
SIMULATION
SPATIAL RESOLUTION
SYMMETRY BREAKING
WOOD