PISCES-RF: A liquid-cooled high-power steady-state helicon plasma device

Saikat Chakraborty Thakur, Michael J. Simmonds, Juan F. Caneses, Fengjen Chang, Eric M. Hollmann, Russell P. Doerner, Richard Goulding, Arnold Lumsdaine, Juergen Rapp, George R. Tynan

Research output: Contribution to journalArticlepeer-review

19 Scopus citations

Abstract

Radio-frequency (RF) driven helicon plasma sources can produce relatively high-density plasmas (n > 1019 m-3) at relatively moderate powers (<2 kW) in argon. However, to produce similar high-density plasmas for fusion relevant gases such as hydrogen (H), deuterium (D) and helium (He), much higher RF powers are needed. For very high RF powers, thermal issues of the RF-transparent dielectric window, used in the RF source design, limit the plasma operation timescales. To mitigate this constraint, we have designed, built and tested a novel helicon plasma source assembly with a fully liquid-cooled RF-transparent window which allows steady state operations at high power (up to 20 kW) and successfully produces high-density plasma with both argon and H. Deionized (DI) water, flowing between two concentric dielectric RF windows, is used as the coolant. We show that a full azimuthal blanket of DI water does not prevent high-density plasma production. From calorimetry on the DI water, we measure the net heat removed by the coolant at steady state conditions. Using infra-red imaging, we calculate the constant plasma heat deposition and measure the final steady state temperature distribution patterns on the inner surface of the ceramic layer. The heat deposition pattern follows the helical shape of the antenna. We also show the consistency between the heat absorbed by the DI water, as measured by calorimetry, and the total heat due to the combined effect of the plasma heating and the absorbed RF. These results are being used to answer critical engineering questions for the 200 kW RF device materials plasma exposure experiment being designed at the Oak Ridge National Laboratory as a next generation plasma material interaction device.

Original languageEnglish
Article number055014
JournalPlasma Sources Science and Technology
Volume30
Issue number5
DOIs
StatePublished - May 2021

Funding

This research is sponsored by the Office of Fusion Energy Sciences, US Department of Energy, under contract DE-FG02-07ER54912. The authors also want to thank Mr. Leopoldo Chousal andMr. Tyler Lynch for their help in technical details on mechanical issues of the source design

Keywords

  • high density hydrogen plasma
  • high power helicon source
  • infra red imaging
  • liquid cooled RF antenna
  • plasma material interaction

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