skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Synergy of two lower hybrid waves with different frequencies on EAST

Journal Article · · Physics of Plasmas
DOI:https://doi.org/10.1063/1.5095653· OSTI ID:1611428
ORCiD logo [1]; ORCiD logo [2];  [2];  [3];  [3]
  1. Chinese Academy of Sciences (CAS), Hefei (China); Univ. of Chinese Academy of Sciences, Beijing (China)
  2. Chinese Academy of Sciences (CAS), Hefei (China)
  3. Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States)

Lower hybrid current drive (LHCD) is one of the major approaches maintaining long pulse discharges on EAST. There are two lower hybrid (LH) systems on EAST launching waves at 4.6 GHz and 2.45 GHz into the plasma, respectively, and the input power of the 4.6 GHz wave is typically dominant. Here, the synergy of the two waves and the modification of the power deposition of the 4.6 GHz wave by coupling the 2.45 GHz wave are investigated theoretically. According to the phase space analysis, the wave propagation domains of the two LH waves always overlap substantially with each other for typical LHCD experimental parameters on EAST, indicating that the coupling between them might be strong. Ray-tracing/Fokker-Planck simulations for a LH current drive experiment on EAST show that the change of the power deposition profile due to the coupling could be understood by the rise and fall of the tails of the parallel electron distribution functions on different flux surfaces. If either the injected wave power at 2.45 GHz is comparable with that at 4.6 GHz or the incident N of the 2.45 GHz wave reaches a high value (e.g., $$5.7/\sqrt{T_{e,0}}$$), the power deposition profile of the 4.6 GHz wave can be modified greatly due to the coupling with the 2.45 GHz wave. With the parameters compatible with the ability of the LH wave system on EAST, injection of the 2.45 GHz wave can still modify the power deposition profile of the 4.6 GHz wave significantly by combining those two approaches. Finally, it is shown how a 4.6 GHz wave which cannot be Landau damped when injected alone is absorbed in low density plasmas with a magnetic shear reversal configuration in the presence of a 2.45 GHz wave.

Research Organization:
Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States)
Sponsoring Organization:
USDOE Office of Science (SC); National Key Research and Development Program of China; National Natural Science Foundation of China (NSFC); National ITER program of China
Grant/Contract Number:
SC0010492; 2017YFE0300400; 11575239; 2015GB101003
OSTI ID:
1611428
Alternate ID(s):
OSTI ID: 1513324
Journal Information:
Physics of Plasmas, Vol. 26, Issue 5; ISSN 1070-664X
Publisher:
American Institute of Physics (AIP)Copyright Statement
Country of Publication:
United States
Language:
English
Citation Metrics:
Cited by: 5 works
Citation information provided by
Web of Science

References (34)

The generalized accessibility and spectral gap of lower hybrid waves in tokamaks journal July 1994
Linear Theory of Lower Hybrid Heating journal January 1984
Review of recent experimental and modeling progress in the lower hybrid range of frequencies at ITER relevant parameters conference January 2014
Confining a Tokamak Plasma with rf-Driven Currents. journal February 1979
Confining a Tokamak Plasma with rf-Driven Currents journal September 1978
Theory of synergy between electron cyclotron and lower hybrid waves journal July 2004
Profile control with lower hybrid waves on ASDEX journal July 1994
Current profile control and improvement of current drive efficiency by combined lower hybrid waves in TRIAM-1M journal March 2000
Progress towards steady-state regimes in Alcator C-Mod journal October 2013
Theoretical analysis of key factors achieving reversed magnetic shear q -profiles sustained with lower hybrid waves on EAST journal February 2019
Combined kinetic and transport modeling of radiofrequency current drive journal December 2000
Chapter 6: Plasma auxiliary heating and current drive journal December 1999
Development of high poloidal beta, steady-state scenario with ITER-like tungsten divertor on EAST journal June 2017
Synergy of Electron-Cyclotron and Lower-Hybrid Current Drive in Steady-State Plasmas journal December 2004
Recent progress on lower hybrid current drive and implications for ITER journal May 2013
Investigation of lower hybrid physics through power modulation experiments on Alcator C-Mod journal May 2011
Vlasov Simulations of Spectral and Fast Electron Features in Lower Hybrid Current Drive journal October 1999
Modelling of the EAST lower-hybrid current drive experiment using GENRAY/CQL3D and TORLH/CQL3D journal October 2014
A quasilinear Fokker-Planck code for the numerical solution of the lower-hybrid current-drive problem in the presence of electron cyclotron heating journal October 1989
General properties of the lower hybrid ray trajectories in toroidal plasmas journal December 1992
Lower hybrid current drive experiments on Alcator C-Mod: Comparison with theory and simulation journal May 2008
Synergy effects during current drive by two lower-hybrid waves journal March 2017
Numerical study of the synergy effects of electron cyclotron wave and two lower-hybrid waves in the current drive process journal August 2017
Advances in modeling of lower hybrid current drive journal February 2016
Enhancement of Absorption of Lower Hybrid Wave by Filling the Spectral Gap journal October 1994
Chapter 6: Steady state operation journal June 2007
Sustainment and modification of reversed magnetic shear by LHCD on JT-60U journal October 1996
Nonlinear Dependence of the Synergetic Current by the Combined Effect of ECCD and LHCD on the Power Ratio on HL-2A Tokamak journal June 2013
Lower hybrid current drive accessibility study with reconstructed magnetic equilibria in PBX-M journal June 1994
Cross-effect on electron cyclotron and lower hybrid current drive in tokamak plasmas journal April 1987
Review of recent experimental and modeling progress in the lower hybrid range of frequencies at ITER relevant parameters journal June 2014
Stationary magnetic shear reversal experiments in Tore Supra journal September 1996
Analysis of performance degradation in an electron heating dominant H-mode plasma after ECRH termination in EAST journal April 2018
Theory of Synergy between Electron Cyclotron and Lower Hybrid Waves text January 2003


Similar Records

Theoretical analysis of key factors achieving reversed magnetic shear q-profiles sustained with lower hybrid waves on EAST
Journal Article · Fri Feb 15 00:00:00 EST 2019 · Plasma Physics and Controlled Fusion · OSTI ID:1611428

Observation of synergy between lower hybrid waves at two frequencies in EAST
Dataset · Tue Jun 15 00:00:00 EDT 2021 · OSTI ID:1611428

Observation of synergy between lower hybrid waves at two frequencies in EAST
Journal Article · Mon Jul 12 00:00:00 EDT 2021 · Physics of Plasmas · OSTI ID:1611428