The Effects of the Scattering by Edge Plasma Density Fluctuations on Lower Hyybrid Wave Propagation
Authors: N. Bertelli, G. Wallace, P.T. Bonoli, R.W. Harvey, A.P. Smirnov, S.G. Baek, R.R. Parker, C.K. Phillips, E.J. Valeo, J.R. Wilson, and J.C. Wright
Abstract:
Scattering effects induced by edge density fluctuations on lower hybrid
(LH) wave propagation are investigated. The scattering model used here is based on
the work of Bonoli and Ott [Phys. Fluids 25 (1982) 361]. It utilizes an electromagnetic
wave kinetic equation solved by a Monte Carlo technique. This scattering model
has been implemented in GENRAY , a ray tracing code which explicitly simulates
wave propagation, as well as collisionless and collisional damping processes, over the
entire plasma discharge, including the scrape-off layer (SOL) that extends from the
separatrix to the vessel wall. A numerical analysis of the LH wave trajectories and
the power deposition profile with and without scattering is presented for Alcator CMod
discharges. Comparisons between the measured hard x-ray emission on Alcator
C-Mod and simulations of the data obtained from the synthetic diagnostic included in
the GENRAY/CQL3D package are shown, with and without the combination of scattering
and collisional damping. Implications of these results on LH current drive are discussed.
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Submitted to: Plasma Physics and Controlled Fusion (August 2012) Presented at: Joint Varenna-Lausanne International Workshop, Varenna, Italy (August 27-31, 2012)
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Download PPPL-4801 (pdf 526 KB 19 pp)
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