Magnetic Reconnection in the Spheromak: Physics and Consequences

Journal Article · Tue Feb 28 04:00:00 EST 2006 · Journal of Fusion Energy

OSTI ID:902234

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

Magnetic reconnection in the spheromak changes magnetic topology by conversion of injected toroidal flux into poloidal flux and by magnetic surface closure (or opening) in a slowly decaying spheromak. Results from the Sustained Spheromak Physics Experiment, SSPX, are compared with resistive MHD simulations using the NIMROD code. Voltage spikes on the SSPX gun during spheromak formation are interpreted as reconnection across a negative-current layer close to the mean-field x-point. Field lines are chaotic during these events, resulting in rapid electron energy loss to the walls and the low T{sub e} < 50 eV seen in experiment and simulation during strong helicity injection. Closure of flux surfaces (and high T{sub e}) can occur between voltage spikes if they are sufficiently far apart in time; these topology changes are not reflected in the impedance of the axisymmetric gun. Possible future experimental scenarios in SSPX are examined in the presence of the constraints imposed by reconnection physics.

• Research Organization: Lawrence Livermore National Laboratory (LLNL), Livermore, CA
• Sponsoring Organization: USDOE
• DOE Contract Number: W-7405-ENG-48
• OSTI ID: 902234
• Report Number(s): UCRL-JRNL-219446
• Journal Information: Journal of Fusion Energy, Journal Name: Journal of Fusion Energy Journal Issue: 1/2 Vol. 26; ISSN JFENDS; ISSN 0164-0313
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
CLOSURES
ELECTRONS
HELICITY
IMPEDANCE
MAGNETIC RECONNECTION
MAGNETIC SURFACES
NIMROD
PHYSICS
SIMULATION
TOPOLOGY