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Title: Phase coherence of parametric-decay modes during high-harmonic fast-wave heating in the National Spherical Torus Experiment

Abstract

Third-order spectral analysis, in particular, the auto bicoherence, was applied to probe signals from high-harmonic fast-wave heating experiments in the National Spherical Torus Experiment. Strong evidence was found for parametric decay of the 30 MHz radio-frequency (RF) pump wave, with a low-frequency daughter wave at 2.7 MHz, the local majority-ion cyclotron frequency. The primary decay modes have auto bicoherence values around 0.85, very close to the theoretical value of one, which corresponds to total phase coherence with the pump wave. The threshold RF pump power for onset of parametric decay was found to be between 200 kW and 400 kW.

Authors:
 [1]; ; ; ;  [2]
  1. Crow Radio and Plasma Science, Princeton, New Jersey 08540 (United States)
  2. Princeton Plasma Physics Laboratory, P.O. Box 451, Princeton, New Jersey 08543-0451 (United States)
Publication Date:
OSTI Identifier:
22598925
Resource Type:
Journal Article
Resource Relation:
Journal Name: Physics of Plasmas; Journal Volume: 23; Journal Issue: 6; Other Information: (c) 2016 Author(s); Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
70 PLASMA PHYSICS AND FUSION TECHNOLOGY; CYCLOTRON FREQUENCY; CYCLOTRONS; DECAY; HEATING; IONS; MHZ RANGE 01-100; NSTX DEVICE; RADIOWAVE RADIATION; SPHERICAL CONFIGURATION

Citation Formats

Carlsson, J. A., E-mail: carlsson@pppl.gov, Wilson, J. R., Hosea, J. C., Greenough, N. L., and Perkins, R. J. Phase coherence of parametric-decay modes during high-harmonic fast-wave heating in the National Spherical Torus Experiment. United States: N. p., 2016. Web. doi:10.1063/1.4954825.
Carlsson, J. A., E-mail: carlsson@pppl.gov, Wilson, J. R., Hosea, J. C., Greenough, N. L., & Perkins, R. J. Phase coherence of parametric-decay modes during high-harmonic fast-wave heating in the National Spherical Torus Experiment. United States. doi:10.1063/1.4954825.
Carlsson, J. A., E-mail: carlsson@pppl.gov, Wilson, J. R., Hosea, J. C., Greenough, N. L., and Perkins, R. J. Wed . "Phase coherence of parametric-decay modes during high-harmonic fast-wave heating in the National Spherical Torus Experiment". United States. doi:10.1063/1.4954825.
@article{osti_22598925,
title = {Phase coherence of parametric-decay modes during high-harmonic fast-wave heating in the National Spherical Torus Experiment},
author = {Carlsson, J. A., E-mail: carlsson@pppl.gov and Wilson, J. R. and Hosea, J. C. and Greenough, N. L. and Perkins, R. J.},
abstractNote = {Third-order spectral analysis, in particular, the auto bicoherence, was applied to probe signals from high-harmonic fast-wave heating experiments in the National Spherical Torus Experiment. Strong evidence was found for parametric decay of the 30 MHz radio-frequency (RF) pump wave, with a low-frequency daughter wave at 2.7 MHz, the local majority-ion cyclotron frequency. The primary decay modes have auto bicoherence values around 0.85, very close to the theoretical value of one, which corresponds to total phase coherence with the pump wave. The threshold RF pump power for onset of parametric decay was found to be between 200 kW and 400 kW.},
doi = {10.1063/1.4954825},
journal = {Physics of Plasmas},
number = 6,
volume = 23,
place = {United States},
year = {Wed Jun 15 00:00:00 EDT 2016},
month = {Wed Jun 15 00:00:00 EDT 2016}
}