Experimental Investigation of the Effects of Magnetic Mirrors on Plasma Transport in the Prototype Material Plasma Exposure Experiment

Nischal Kafle; Juan Francisco Caneses Marin; Theodore M. Biewer; Richard H. Goulding; John B.O. Caughman; David C. Donovan; Cornwall Lau; Juergen Rapp

doi:10.1109/TPS.2020.2974228

Experimental Investigation of the Effects of Magnetic Mirrors on Plasma Transport in the Prototype Material Plasma Exposure Experiment

Nischal Kafle, Juan Francisco Caneses Marin, Theodore M. Biewer, Richard H. Goulding, John B.O. Caughman, David C. Donovan, Cornwall Lau, Juergen Rapp

Research output: Contribution to journal › Article › peer-review

6 Scopus citations

Abstract

The Prototype Material Plasma Exposure eXperiment (Proto-MPEX) at Oak Ridge National Laboratory is developing a helicon radio frequency (RF) source for plasma production along with microwave electron heating and RF ion heating. Proto-MPEX has several magnetic mirrors that affect plasma transport. The magnetic field near the helicon source is 0.05 T, and the peak magnetic field in Proto-MPEX is 1.8 T, which results in a large magnetic well for particles sourced at the helicon transporting toward the target region. Keeping the helicon source field and the target field constant, experiments have been conducted by methodically changing the magnetic field, at a local axial location, within the source and the target. Plasma flow measurements using Mach probes have shown a decrease in the flow as a function of the magnetic mirror ratio. Plasma flows were further investigated with ion cyclotron resonant heating (ICH). Results with the addition of ICH measured upstream of the antenna have shown a decrease in Mach number as a function of mirror ratio when compared to helicon discharges. Such flow behavior demonstrated slowing down of the plasma due to the increased reverse plasma flow toward the helicon plasma source. However, in high magnetic fields, when the resonant magnetic field moved away from the ICH antenna, no effects on the plasma flow due to ICH were observed.

Original language	English
Article number	9011572
Pages (from-to)	1396-1402
Number of pages	7
Journal	IEEE Transactions on Plasma Science
Volume	48
Issue number	6
DOIs	https://doi.org/10.1109/TPS.2020.2974228
State	Published - Jun 2020

Funding

This work was supported by UT-Battelle, LLC, with the U.S. Department of Energy under Contract DE-AC05-00OR22725. The review of this article was arranged by Senior Editor G. H. Neilson. (Corresponding author: Nischal Kafle.) Manuscript received July 19, 2019; revised January 15, 2020; accepted January 30, 2020. Date of publication February 25, 2020; date of current version June 10, 2020. This work was supported by UT-Battelle, LLC, with the U.S. Department of Energy under Contract DE-AC05-00OR22725. The review of this article was arranged by Senior Editor G. H. Neilson. (Corresponding author: Nischal Kafle.) Nischal Kafle and David C. Donovan are with the Department of Nuclear Engineering, University of Tennessee-Knoxville, Knoxville, TN 37996 USA (e-mail: [email protected]; [email protected]).

Funders	Funder number
UT-Battelle, LLC
U.S. Department of Energy	DE-AC05-00OR22725
UT-Battelle

Keywords

Electron density
Prototype Material Plasma Exposure eXperiment (Proto-MPEX)
electron temperature
linear device
magnetic confinement
magnetic fields
magnetic mirrors
plasma measurements

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10.1109/TPS.2020.2974228

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Kafle, N., Caneses Marin, J. F., Biewer, T. M., Goulding, R. H., Caughman, J. B. O., Donovan, D. C., Lau, C., & Rapp, J. (2020). Experimental Investigation of the Effects of Magnetic Mirrors on Plasma Transport in the Prototype Material Plasma Exposure Experiment. IEEE Transactions on Plasma Science, 48(6), 1396-1402. Article 9011572. https://doi.org/10.1109/TPS.2020.2974228

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abstract = "The Prototype Material Plasma Exposure eXperiment (Proto-MPEX) at Oak Ridge National Laboratory is developing a helicon radio frequency (RF) source for plasma production along with microwave electron heating and RF ion heating. Proto-MPEX has several magnetic mirrors that affect plasma transport. The magnetic field near the helicon source is 0.05 T, and the peak magnetic field in Proto-MPEX is 1.8 T, which results in a large magnetic well for particles sourced at the helicon transporting toward the target region. Keeping the helicon source field and the target field constant, experiments have been conducted by methodically changing the magnetic field, at a local axial location, within the source and the target. Plasma flow measurements using Mach probes have shown a decrease in the flow as a function of the magnetic mirror ratio. Plasma flows were further investigated with ion cyclotron resonant heating (ICH). Results with the addition of ICH measured upstream of the antenna have shown a decrease in Mach number as a function of mirror ratio when compared to helicon discharges. Such flow behavior demonstrated slowing down of the plasma due to the increased reverse plasma flow toward the helicon plasma source. However, in high magnetic fields, when the resonant magnetic field moved away from the ICH antenna, no effects on the plasma flow due to ICH were observed.",

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author = "Nischal Kafle and {Caneses Marin}, {Juan Francisco} and Biewer, {Theodore M.} and Goulding, {Richard H.} and Caughman, {John B.O.} and Donovan, {David C.} and Cornwall Lau and Juergen Rapp",

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Experimental Investigation of the Effects of Magnetic Mirrors on Plasma Transport in the Prototype Material Plasma Exposure Experiment

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