Open AccessEnhancement of Mode-converted Electron Bernstein Wave Emission during NSTX H-mode Plasmas
Author(s) -
G. Taylor,
P. C. Efthimion,
B. Jones,
B.P. LeBlanc,
R. Maingi
Publication year - 2001
Language(s) - English
Resource type - Reports
DOI - 10.2172/787904
Subject(s) - plasma , torus , mode (computer interface) , atomic physics , electron density , electron , polarization (electrochemistry) , electromagnetic radiation , physics , magnetic field , computational physics , optics , chemistry , nuclear physics , geometry , mathematics , computer science , operating system , quantum mechanics
A sudden, threefold increase in emission from fundamental electrostatic electron Bernstein waves (EBW) which mode convert and tunnel to the electromagnetic X-mode has been observed during H-mode [high-confinement mode] transitions on the National Spherical Torus Experiment (NSTX) spherical torus plasma. The mode-converted EBW emission viewed normal to the magnetic field on the plasma midplane increases when the density profile steepens in the vicinity of the mode-conversion layer, which is located in the plasma scrape off. The measured conversion efficiency during the H-mode is consistent with the calculated EBW to X-mode conversion efficiency derived using edge density data. Calculations indicate that there may also be a small residual contribution to the measured X-mode electromagnetic radiation from polarization-scrambled, O-mode emission, converted from EBWs