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

Title: Linear properties of energetic particle driven geodesic acoustic mode

Abstract

Linear properties of energetic particle driven geodesic acoustic mode (EGAM) in the large helical device plasmas are investigated using a hybrid simulation code for a magnetohydrodynamics fluid interacting with energetic particles. It is found that the EGAM is a global mode with the spatially uniform oscillation frequency despite the spatial variation of the local geodesic acoustic mode frequency. The poloidal mode numbers of poloidal velocity fluctuation, plasma density fluctuation, and magnetic fluctuation are m = 0, 1, and 2, respectively. Oscillation frequency, linear growth rate, and spatial width of EGAM are compared for different physics conditions. The EGAM frequency is proportional to the square root of the plasma temperature. The frequency is lower for higher energetic particle {beta} value. The mode spatial width is larger for larger spatial width of the energetic particle distribution and for the reversed shear safety-factor profile than the normal shear profile. It is also found that the EGAM propagates radially outward in the linearly growing phase, and the propagation speed is slower for the spatially broadened modes.

Authors:
 [1];  [1]
  1. Graduate University for Advanced Studies, Toki 509-5292 (Japan)
Publication Date:
OSTI Identifier:
22113352
Resource Type:
Journal Article
Journal Name:
Physics of Plasmas
Additional Journal Information:
Journal Volume: 20; Journal Issue: 1; Other Information: (c) 2013 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA); Journal ID: ISSN 1070-664X
Country of Publication:
United States
Language:
English
Subject:
70 PLASMA PHYSICS AND FUSION TECHNOLOGY; ELECTRON TEMPERATURE; FLUCTUATIONS; FLUIDS; ION TEMPERATURE; LHD DEVICE; MAGNETOHYDRODYNAMICS; OSCILLATIONS; PLASMA; PLASMA DENSITY; PLASMA SIMULATION; PLASMA WAVES; REVERSED SHEAR; SHEAR; STELLARATORS

Citation Formats

Wang, Hao, Todo, Yasushi, and National Institute for Fusion Science, Toki 509-5292. Linear properties of energetic particle driven geodesic acoustic mode. United States: N. p., 2013. Web. doi:10.1063/1.4774410.
Wang, Hao, Todo, Yasushi, & National Institute for Fusion Science, Toki 509-5292. Linear properties of energetic particle driven geodesic acoustic mode. United States. https://doi.org/10.1063/1.4774410
Wang, Hao, Todo, Yasushi, and National Institute for Fusion Science, Toki 509-5292. 2013. "Linear properties of energetic particle driven geodesic acoustic mode". United States. https://doi.org/10.1063/1.4774410.
@article{osti_22113352,
title = {Linear properties of energetic particle driven geodesic acoustic mode},
author = {Wang, Hao and Todo, Yasushi and National Institute for Fusion Science, Toki 509-5292},
abstractNote = {Linear properties of energetic particle driven geodesic acoustic mode (EGAM) in the large helical device plasmas are investigated using a hybrid simulation code for a magnetohydrodynamics fluid interacting with energetic particles. It is found that the EGAM is a global mode with the spatially uniform oscillation frequency despite the spatial variation of the local geodesic acoustic mode frequency. The poloidal mode numbers of poloidal velocity fluctuation, plasma density fluctuation, and magnetic fluctuation are m = 0, 1, and 2, respectively. Oscillation frequency, linear growth rate, and spatial width of EGAM are compared for different physics conditions. The EGAM frequency is proportional to the square root of the plasma temperature. The frequency is lower for higher energetic particle {beta} value. The mode spatial width is larger for larger spatial width of the energetic particle distribution and for the reversed shear safety-factor profile than the normal shear profile. It is also found that the EGAM propagates radially outward in the linearly growing phase, and the propagation speed is slower for the spatially broadened modes.},
doi = {10.1063/1.4774410},
url = {https://www.osti.gov/biblio/22113352}, journal = {Physics of Plasmas},
issn = {1070-664X},
number = 1,
volume = 20,
place = {United States},
year = {2013},
month = {1}
}