On self‐consistent ray‐tracing and Fokker–Planck modeling of the hard x‐ray emission during lower‐hybrid current drive in tokamaks

• Published in: Physics of fluids. B, Plasma physics Plasma physics, 1993-09, Vol.5 (9), p.3276-3283
• Main Authors: Bizarro, João P., Peysson, Yves, Bonoli, Paul T., Carrasco, Joël, de Wit, Thierry Dudok, Fuchs, Vladimir, Hoang, Gia T., Litaudon, Xavier, Moreau, Didier, Pocheau, Christine, Shkarofsky, Issie P.
• Format: Article
• Language: English
• Subjects: 70 PLASMA PHYSICS AND FUSION TECHNOLOGY; 700350 - Plasma Production, Heating, Current Drive, & Interactions- (1992-); CHEMICAL ANALYSIS; CLOSED PLASMA DEVICES; COMPUTER CODES; DIFFERENTIAL EQUATIONS; DISTRIBUTION FUNCTIONS; Emission, absorption, and scattering of x and γ radiation; EQUATIONS; Exact sciences and technology; FOKKER-PLANCK EQUATION; FUNCTIONS; HEATING; LOWER HYBRID CURRENT DRIVE; Magnetic confinement and equilibrium; NON-INDUCTIVE CURRENT DRIVE; NONDESTRUCTIVE ANALYSIS; PARTIAL DIFFERENTIAL EQUATIONS; Physics; Physics of gases, plasmas and electric discharges; Physics of plasmas and electric discharges; PLASMA HEATING; Plasma heating (beam injection, radio-frequency and microwave, ohmic, icr, ecr and current drive heating); Plasma production and heating; Plasma properties; THERMONUCLEAR DEVICES; TOKAMAK DEVICES; Tokamaks; X-RAY EMISSION ANALYSIS
• ISSN: 0899-8221; 2163-503X
• DOI: 10.1063/1.860664

A detailed investigation is presented on the ability of combined ray‐tracing and Fokker–Planck calculations to predict the hard x‐ray (HXR) emission during lower‐hybrid (LH) current drive in tokamaks when toroidally induced ray stochasticity is important. A large number of rays is used and the electron distribution function is obtained by self‐consistently iterating the appropriate power deposition and Fokker–Planck calculations. It is shown that effects due to radial diffusion of suprathermal electrons and to radiation scattering by the inner wall can be significant. The experimentally observed features of the HXR emission are fairly well predicted, thus confirming that combined ray‐tracing and Fokker–Planck codes are capable of correctly modeling the physics of LH current drive in tokamaks.