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

Carlsson, J. ; Wilson, J. R. ; Hosea, J. ; Greenough, N. ; Perkins, R.
Issue date: 2016
Rights:
Creative Commons Attribution 4.0 International (CC BY)
Cite as:
Carlsson, J., Wilson, J. R., Hosea, J., Greenough, N., & Perkins, R. (2016). Phase coherence of parametric-decay modes during high-harmonic fast-wave heating in the National Spherical Torus Experiment [Data set]. Princeton Plasma Physics Laboratory, Princeton University. https://doi.org/10.11578/1366987
@electronic{carlsson_j_2016,
  author      = {Carlsson, J. and
                Wilson, J. R. and
                Hosea, J. and
                Greenough, N. and
                Perkins, R.},
  title       = {{Phase coherence of parametric-decay mode
                s during high-harmonic fast-wave heating
                 in the National Spherical Torus Experim
                ent}},
  publisher   = {{Princeton Plasma Physics Laboratory, Pri
                nceton University}},
  year        = 2016,
  url         = {https://doi.org/10.11578/1366987}
}
Description:

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.

Show More