A fully relaxed helicity balance model for an inductively driven spheromak

Journal Article · Thu Nov 15 04:00:00 EST 2007 · Physics of Plasmas

DOI:https://doi.org/10.1063/1.2801410· OSTI ID:21069887

O'Neill, R G; Marklin, G J; Jarboe, T R; Akcay, C; Hamp, W T; Nelson, B A; Redd, A J; Smith, R J; Stewart, B T; Wrobel, J S; Sieck, P E ^[1]

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1. University of Washington, Box 352250, Seattle, Washington 98195 (United States)

Magnetic helicity balance and a fully relaxed Taylor-state model are shown to predict the magnitude of sustained equilibrium current in an inductively driven spheromak. The Helicity Injected Torus with Steady Inductive drive (HIT-SI) [T. R. Jarboe et al., Phys. Rev. Lett. 97, 115003 (2006)] forms and sustains spheromaks using two inductively driven helicity injectors. By assuming helicity is injected at a rate 2V{psi}, and only decays through Spitzer resistivity using T{sub e} measured with a Langmuir probe, the magnitude of the sustained equilibrium current is predicted with no fitting parameters. The model correctly predicts a threshold helicity injection rate for spheromak formation. Although the experimental results suggest a higher effective helicity dissipation rate by a factor of {approx}1.37 compared to the Spitzer value, the prediction is still within the uncertainties of the measured parameters.

• OSTI ID: 21069887
• Journal Information: Physics of Plasmas, Journal Name: Physics of Plasmas Journal Issue: 11 Vol. 14; ISSN PHPAEN; ISSN 1070-664X
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
ELECTRIC CONDUCTIVITY
ELECTRIC CURRENTS
EQUILIBRIUM
HELICITY
LANGMUIR PROBE
PLASMA
PLASMA CONFINEMENT
RELAXATION
SPHEROMAK DEVICES
SPITZER THEORY