Observations of electron heating during 28 GHz microwave power application in proto-MPEX

Journal Article · Tue Feb 20 00:00:00 EST 2018 · Physics of Plasmas

DOI:https://doi.org/10.1063/1.5018479· OSTI ID:1429196

Biewer, Theodore M.  ^[1]; Bigelow, Tim S.  ^[1]; Caneses Marin, Juan F.  ^[1]; Diem, Stephanie J.  ^[1]; Green, David L.  ^[1]; Kafle, Nischal ^[1]; Rapp, Juergen  ^[1]

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1. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

The Prototype Material Plasma Exposure Experiment at the Oak Ridge National Laboratory utilizes a variety of power systems to generate and deliver a high heat flux plasma onto the surface of material targets. In the experiments described here, a deuterium plasma is produced via a ~100 kW, 13.56 MHz RF helicon source, to which ~20 kW of 28 GHz microwave power is applied. The electron density and temperature profiles are measured using a Thomson scattering (TS) diagnostic, and indicate that the electron density is centrally peaked. In the core of the plasma column, the electron density is higher than the cut-off density (~0.9 × 1019 m^-3) for the launched mixture of X- and O-mode electron cyclotron heating waves to propagate. TS measurements indicate electron temperature increases from ~5 eV to ~20 eV during 28 GHz power application when the neutral deuterium pressure is reduced below 0.13 Pa (~1 mTorr.).

• Research Organization: Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
• Sponsoring Organization: USDOE
• Contributing Organization: Proto-MPEX Team
• Grant/Contract Number: AC05-00OR22725
• OSTI ID: 1429196
• Alternate ID(s): OSTI ID: 1421892
• Journal Information: Physics of Plasmas, Vol. 25, Issue 2; ISSN 1070-664X
• Publisher: American Institute of Physics (AIP)
• Country of Publication: United States
• Language: English

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70 PLASMA PHYSICS AND FUSION TECHNOLOGY