title: Dynamic Stark spectroscopic measurements of microwave electric fields inside the plasma near a high-power antenna.
abstract: Fully dynamic Stark effect visible spectroscopy was used for the first time to directly measure the local rf electric field in the boundary plasma near a high-power antenna in high-performance, magnetically confined, fusion energy experiment. The measurement was performed in the superconducting tokamak Tore Supra, in the near field of a 1–3 MW, lower-hybrid, 3.7 GHz wave-launch antenna, and combined with modeling of neutral atom transport to estimate the local rf electric field amplitude (as low as 1–2 kV/cm) and direction in this region. The measurement was then shown to be consistent with the predicted values from a 2D full-wave propagation model. Notably the measurement confirmed that the electric field direction deviates substantially from the direction in which it is launched by the waveguides as it penetrates only a few cm radially inward into the plasma from the waveguides, consistent with the model.
authors.affiliation: Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831-6169, USA. kleppercc@ornl.gov
authors.forename: C C
authors.initials: CC
authors.lastname: Klepper
authors.forename: R C
authors.initials: RC
authors.lastname: Isler
authors.forename: J
authors.initials: J
authors.lastname: Hillairet
authors.forename: E H
authors.initials: EH
authors.lastname: Martin
authors.forename: L
authors.initials: L
authors.lastname: Colas
authors.forename: A
authors.initials: A
authors.lastname: Ekedahl
authors.forename: M
authors.initials: M
authors.lastname: Goniche
authors.forename: J H
authors.initials: JH
authors.lastname: Harris
authors.forename: D L
authors.initials: DL
authors.lastname: Hillis
authors.forename: S
authors.initials: S
authors.lastname: Panayotis
authors.forename: B
authors.initials: B
authors.lastname: Pegourié
authors.forename: Ph
authors.initials: P
authors.lastname: Lotte
authors.forename: G
authors.initials: G
authors.lastname: Colledani
authors.forename: V
authors.initials: V
authors.lastname: Martin