Observation of divertor currents during type-I ELMs on the DIII-D tokamak

Knolker, M.; Evans, T. E.; Wingen, A.; Bortolon, A.; Chrystal, C.; Laggner, F.; Moyer, R. A.; Nazikian, R.; Zohm, H.

doi:10.1016/j.nme.2019.01.003

Title: Observation of divertor currents during type-I ELMs on the DIII-D tokamak

Journal Article · Tue Jan 01 00:00:00 EST 2019 · Nuclear Materials and Energy

DOI:https://doi.org/10.1016/j.nme.2019.01.003· OSTI ID:1547897

Knolker, M.; Evans, T. E.; Wingen, A.; Bortolon, A.; Chrystal, C.;

; Moyer, R. A.; Nazikian, R.; Zohm, H.

In DIII-D, large currents flowing into the divertor floor during edge-localized modes (ELMs) have been measured by an array of shunt current resistors before an increase of heat flux is measured by IR thermography. The diagnostic consists of 40 tiles distributed in five concentric circles in the lower divertor with sampling rates range between 50 and 500 kHz. Typically, the current measured by a single tile during an ELM can reach 500 A. This amounts to 5–25 kA flowing in the divertor tiles. The temporal evolution of the ELM currents shows a first phase with large amplitude oscillations, occurring before the heat flux increase measured by infrared thermography at the same location, lasting between 0.05 ms and 0.3 ms. A second phase follows where the time evolution of the divertor current mimics the evolution of the divertor heat flux. These currents could affect the plasma edge stability in the nonlinear ELM phase and provide a mechanism leading to explosive growth of edge stochasticity, the need of which and existence is predicted in contemporary nonlinear ELM simulations.

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Research Organization:: General Atomics, San Diego, CA (United States); Univ. of California, San Diego, CA (United States); Princeton Plasma Physics Laboratory (PPPL), Princeton, NJ (United States); Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States)

Sponsoring Organization:: USDOE Office of Science (SC), Fusion Energy Sciences (FES)

Grant/Contract Number:: FC02-04ER54698; FG02-07ER54917; FG02-05ER54809; AC05-00OR22725

OSTI ID:: 1547897

Alternate ID(s):: OSTI ID: 1502366; OSTI ID: 1570890

Journal Information:: Nuclear Materials and Energy, Journal Name: Nuclear Materials and Energy Vol. 18 Journal Issue: C; ISSN 2352-1791

Publisher:: ElsevierCopyright Statement

Country of Publication:: Netherlands

Language:: English

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Cited by: 4 works

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Cited By (1)

On the possiblity of direct electrical power extraction from scrape-off layer currents in tokamaks Komm, M.; Stockel, J.; Adamek, J. Plasma Physics and Controlled Fusion, Vol. 61, Issue 9 https://doi.org/10.1088/1361-6587/ab2739	journal	August 2019