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Title: Direct Observation of Nonlinear Coupling between Pedestal Modes Leading to the Onset of Edge Localized Modes

Abstract

Prior to eruptive events such as edge localized modes (ELMs), quasicoherent fluctuations, referred to as pedestal modes, are observed in the edge of fusion devices. We report on the investigations of nonlinear coupling between these modes during quasistationary inter-ELM phases leading to the ELM onset. Three dominant modes, with density and magnetic signatures, are identified as key players in the triggering mechanism of certain classes of ELMs. We demonstrate that one of these modes is amplified by the two others through three wave interactions. The amplified mode is radially shifted relative to the other two modes towards the last-closed flux surface as the ELM event approaches. Here, our results suggest that nonlinear coupling of pedestal modes, associated with radial distortions pushing out of the pedestal, is a possible mechanism for the triggering of low frequency ELMs relevant for future fusion devices.

Authors:
 [1];  [1];  [2];  [1];  [1];  [3]
  1. Princeton Plasma Physics Lab. (PPPL), Princeton, NJ (United States)
  2. Univ. of California, Los Angeles, CA (United States)
  3. Univ. of Wisconsin, Madison, WI (United States)
Publication Date:
Research Org.:
Princeton Plasma Physics Lab. (PPPL), Princeton, NJ (United States)
Sponsoring Org.:
USDOE Office of Science (SC), Fusion Energy Sciences (FES) (SC-24)
OSTI Identifier:
1485145
Alternate Identifier(s):
OSTI ID: 1484327
Grant/Contract Number:  
AC02-09CH11466; FG02-08ER54999; FG02-08ER54984; FC02- 04ER54698; DEFC02- 04ER54698
Resource Type:
Journal Article: Accepted Manuscript
Journal Name:
Physical Review Letters
Additional Journal Information:
Journal Volume: 121; Journal Issue: 23; Journal ID: ISSN 0031-9007
Publisher:
American Physical Society (APS)
Country of Publication:
United States
Language:
English
Subject:
70 PLASMA PHYSICS AND FUSION TECHNOLOGY

Citation Formats

Diallo, A., Dominski, J., Barada, K., Knolker, M., Kramer, G. J., and McKee, G. Direct Observation of Nonlinear Coupling between Pedestal Modes Leading to the Onset of Edge Localized Modes. United States: N. p., 2018. Web. doi:10.1103/PhysRevLett.121.235001.
Diallo, A., Dominski, J., Barada, K., Knolker, M., Kramer, G. J., & McKee, G. Direct Observation of Nonlinear Coupling between Pedestal Modes Leading to the Onset of Edge Localized Modes. United States. doi:10.1103/PhysRevLett.121.235001.
Diallo, A., Dominski, J., Barada, K., Knolker, M., Kramer, G. J., and McKee, G. Mon . "Direct Observation of Nonlinear Coupling between Pedestal Modes Leading to the Onset of Edge Localized Modes". United States. doi:10.1103/PhysRevLett.121.235001.
@article{osti_1485145,
title = {Direct Observation of Nonlinear Coupling between Pedestal Modes Leading to the Onset of Edge Localized Modes},
author = {Diallo, A. and Dominski, J. and Barada, K. and Knolker, M. and Kramer, G. J. and McKee, G.},
abstractNote = {Prior to eruptive events such as edge localized modes (ELMs), quasicoherent fluctuations, referred to as pedestal modes, are observed in the edge of fusion devices. We report on the investigations of nonlinear coupling between these modes during quasistationary inter-ELM phases leading to the ELM onset. Three dominant modes, with density and magnetic signatures, are identified as key players in the triggering mechanism of certain classes of ELMs. We demonstrate that one of these modes is amplified by the two others through three wave interactions. The amplified mode is radially shifted relative to the other two modes towards the last-closed flux surface as the ELM event approaches. Here, our results suggest that nonlinear coupling of pedestal modes, associated with radial distortions pushing out of the pedestal, is a possible mechanism for the triggering of low frequency ELMs relevant for future fusion devices.},
doi = {10.1103/PhysRevLett.121.235001},
journal = {Physical Review Letters},
number = 23,
volume = 121,
place = {United States},
year = {Mon Dec 03 00:00:00 EST 2018},
month = {Mon Dec 03 00:00:00 EST 2018}
}

Journal Article:
Free Publicly Available Full Text
This content will become publicly available on December 3, 2019
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