Effect of Applied Toroidal Electric Field on the Growth/Decay of Plateau-Phase Runaway Electron Currents in DIII-D

Journal Article · Sat Jan 01 00:00:00 EST 2011 · Nuclear Fusion

DOI:https://doi.org/10.1088/0029-5515/51/10/103026· OSTI ID:1037085

Hollmann, E M ^[1]; Parks, P B ^[2]; Humphrey, D A ^[3]; Brooks, N H ^[3]; Commaux, Nicolas JC ^[4]; Eidietis, N W ^[3]; Evans, T E ^[3]; James, A N ^[1]; Jernigan, T C ^[5]; Jernigan, Thomas C ^[4]; Munoz, J ^[6]; Strait, E J ^[3]; Tsui, C ^[7]; Wesley, J C ^[2]; Yu, J H ^[1]

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1. University of California, San Diego
2. General Atomics
3. General Atomics, San Diego
4. ORNL
5. Oak Ridge National Laboratory (ORNL)
6. Oak Ridge Associated Universities (ORAU)
7. University of Toronto, Toronto, ON, Canada

Large relativistic runaway electron currents (0.1-0.5 MA) persisting for similar to 100 ms are created in the DIII-D tokamak during rapid discharge shut down caused by argon pellet injection. Slow upward and downward ramps in runaway currents were found in response to externally applied loop voltages. Comparison between the observed current growth/decay rate and the rate expected from the knock-on avalanche mechanism suggests that classical collisional dissipation of runaways alone cannot account for the measured growth/damping rates. It appears that a fairly constant anomalous dissipation rate of order 10 s(-1) exists, possibly stemming from radial transport or direct orbit losses to the vessel walls, although the possibility of an apparent loss due to current profile shrinking cannot be ruled out at present.

• Research Organization: Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
• Sponsoring Organization: USDOE Office of Science (SC)
• DOE Contract Number: DE-AC05-00OR22725
• OSTI ID: 1037085
• Journal Information: Nuclear Fusion, Vol. 51, Issue 10
• Country of Publication: United States
• Language: English