Probing the plasma near high power wave launchers in fusion devices for static and dynamic electric fields

Journal Article · Wed Jan 01 00:00:00 EST 2014 · Reviews of Scientific Instruments

DOI:https://doi.org/10.1063/1.4890247· OSTI ID:1150374

Klepper, C Christopher ^[1]; Martin, Elijah H ^[1]; Isler, Ralph C ^[1]; Colas, L. ^[2]; Goniche, M. ^[2]; Hillairet, J. ^[3]; Panayotis, Stephanie ^[3]; Jacquot, Jonathan ^[3]; Lotte, Ph. ^[2]; Colledani, G. ^[3]; Biewer, Theodore M ^[1]; Caughman, J. B. O. ^[4]; Ekedahl, A. ^[3]; Green, David L ^[1]; Harris, Jeffrey H ^[1]; Hillis, Donald Lee ^[1]; Shannon, Prof. Steven ^[5]; Litaudon, X ^[6]

---

1. ORNL
2. French Atomic Energy Commission (CEA), Cadarache, St. Paul lez Durance
3. French Atomic Energy Commission (CEA), Institute for Magnetic Fusion Research (IRFM)
4. Oak Ridge National Laboratory (ORNL)
5. North Carolina State University
6. French Atomic Energy Commission (CEA)

An exploratory study was carried out in the long-pulse tokamak Tore Supra, to determine if electric fields in the plasma around high-power, RF wave launchers could be measured with non-intrusive, passive, optical emission spectroscopy. The focus was in particular on the use of the external electric field Stark effect. The feasibility was found to be strongly dependent on the spatial extent of the electric fields and overlap between regions of strong (> 1 kV/cm) electric fields and regions of plasma particle recycling and plasma-induced, spectral line emission. Most amenable to the measurement was the RF electric field in edge plasma, in front of a lower hybrid heating and current drive launcher. Electric field strengths and direction, derived from fitting the acquired spectra to a model including time-dependent Stark effect and the tokamak-range magnetic field Zeeman-effect, were found to be in good agreement with full-wave modeling of the observed launcher.

• 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: 1150374
• Journal Information: Reviews of Scientific Instruments, Vol. 85, Issue 11; ISSN 0034--6748
• Country of Publication: United States
• Language: English