Title: Modelling of the EAST lower-hybrid current drive experiment using GENRAY/CQL3D and TORLH/CQL3D

Abstract

The coupled GENRAY-CQL3D code has been used to do systematic ray-tracing and Fokker–Planck analysis for EAST Lower Hybrid wave Current Drive (LHCD) experiments. Despite being in the weak absorption regime, the experimental level of LH current drive is successfully simulated, by taking into account the variations in the parallel wavenumber due to the toroidal effect. The effect of radial transport of the fast LH electrons in EAST has also been studied, which shows that a modest amount of radial transport diffusion can redistribute the fast LH current significantly. Taking advantage of the new capability in GENRAY, the actual Scrape Off Layer (SOL) model with magnetic field, density, temperature, and geometry is included in the simulation for both the lower and the higher density cases, so that the collisional losses of Lower Hybrid Wave (LHW) power in the SOL has been accounted for, which together with fast electron losses can reproduce the LHCD experimental observations in different discharges of EAST. We have also analyzed EAST discharges where there is a significant ohmic contribution to the total current, and good agreement with experiment in terms of total current has been obtained. Also, the full-wave code TORLH has been used for the simulationmore » of the LH physics in the EAST, including full-wave effects such as diffraction and focusing which may also play an important role in bridging the spectral gap. The comparisons between the GENRAY and the TORLH codes are done for both the Maxwellian and the quasi-linear electron Landau damping cases. In conclusion, these simulations represent an important addition to the validation studies of the GENRAY-CQL3D and TORLH models being used in weak absorption scenarios of tokamaks with large aspect ratio.« less

Authors:

Yang, C. ^[1]; Bonoli, P. T. ^[2]; Wright, J. C. ^[2]; Ding, B. J. ^[1]; Parker, R. ^[2]; Shiraiwa, S. ^[1]; Li, M. H. ^[1]

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+ Show Author Affiliations

1. Chinese Academy of Sciences (CAS), Hefei (China)
2. Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States). Plasma Science and Fusion Center

Publication Date:

Tue Oct 14 00:00:00 EDT 2014

Research Org.:

Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States)

Sponsoring Org.:

USDOE Office of Science (SC), Fusion Energy Sciences (FES)

OSTI Identifier:

1557616

Grant/Contract Number:  

FC02-99ER54512

Resource Type:

Accepted Manuscript

Journal Name:

Plasma Physics and Controlled Fusion

Additional Journal Information:

Journal Volume: 56; Journal Issue: 12; Journal ID: ISSN 0741-3335

Publisher:

IOP Science

Country of Publication:

United States

Language:

English

Subject:

70 PLASMA PHYSICS AND FUSION TECHNOLOGY