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Title: Quasistationary Plasma Predator-Prey System of Coupled Turbulence, Drive, and Sheared E × B Flow During High Performance DIII-D Tokamak Discharges [A New, Quasi-stationary Plasma Predator-Prey System of Coupled Turbulence, Drive, and Sheared E × B Flow During High Performance DIII-D Tokamak Discharges]

Abstract

A new, long-lived limit cycle oscillation (LCO) regime has been observed in the edge of near zero torque high-performance DIII-D tokamak plasma discharges. These LCOs are localized and comprised of density turbulence, gradient drives, and E X B velocity shear damping (E and B are the local radial electric and total magnetic fields). Density turbulence sequentially acts as a predator (via turbulence transport) of profile gradients and a prey (via shear suppression) to the E X B velocity shear. Reported here for the first time, a unique spatiotemporal variation of the local E X B velocity which is found to be essential for the existence of this system. The LCO system is quasi-stationary, existing from 3 to 12 plasma energy confinement times (~30 to 900 LCO cycles) limited by hardware constraints. In conclusion, this plasma system appears to contribute strongly to the edge transport in these high-performance and transient-free plasmas as evident from oscillations in transport relevant edge parameters at LCO timescale.

Authors:
 [1];  [1];  [2];  [1];  [1];  [2];  [2];  [1]
  1. Univ. of California, Los Angeles, CA (United States)
  2. General Atomics, San Diego, CA (United States)
Publication Date:
Research Org.:
General Atomics, San Diego, CA (United States)
Sponsoring Org.:
USDOE
OSTI Identifier:
1435650
Alternate Identifier(s):
OSTI ID: 1429938
Grant/Contract Number:  
FC02-04ER54698; FG02-08ER54984
Resource Type:
Accepted Manuscript
Journal Name:
Physical Review Letters
Additional Journal Information:
Journal Volume: 120; Journal Issue: 13; Journal ID: ISSN 0031-9007
Publisher:
American Physical Society (APS)
Country of Publication:
United States
Language:
English
Subject:
70 PLASMA PHYSICS AND FUSION TECHNOLOGY; magnetic confinement fusion; nonlinear phenomena in plasmas; plasma turbulence

Citation Formats

Barada, Kshitish, Rhodes, Terry L., Burrell, Keith H., Zeng, L., Bardoczi, Laszlo, Chen, Xi, Muscatello, Christopher M., and Peebles, W. A. Quasistationary Plasma Predator-Prey System of Coupled Turbulence, Drive, and Sheared E×B Flow During High Performance DIII-D Tokamak Discharges [A New, Quasi-stationary Plasma Predator-Prey System of Coupled Turbulence, Drive, and Sheared E×B Flow During High Performance DIII-D Tokamak Discharges]. United States: N. p., 2018. Web. doi:10.1103/PhysRevLett.120.135002.
Barada, Kshitish, Rhodes, Terry L., Burrell, Keith H., Zeng, L., Bardoczi, Laszlo, Chen, Xi, Muscatello, Christopher M., & Peebles, W. A. Quasistationary Plasma Predator-Prey System of Coupled Turbulence, Drive, and Sheared E×B Flow During High Performance DIII-D Tokamak Discharges [A New, Quasi-stationary Plasma Predator-Prey System of Coupled Turbulence, Drive, and Sheared E×B Flow During High Performance DIII-D Tokamak Discharges]. United States. https://doi.org/10.1103/PhysRevLett.120.135002
Barada, Kshitish, Rhodes, Terry L., Burrell, Keith H., Zeng, L., Bardoczi, Laszlo, Chen, Xi, Muscatello, Christopher M., and Peebles, W. A. Tue . "Quasistationary Plasma Predator-Prey System of Coupled Turbulence, Drive, and Sheared E×B Flow During High Performance DIII-D Tokamak Discharges [A New, Quasi-stationary Plasma Predator-Prey System of Coupled Turbulence, Drive, and Sheared E×B Flow During High Performance DIII-D Tokamak Discharges]". United States. https://doi.org/10.1103/PhysRevLett.120.135002. https://www.osti.gov/servlets/purl/1435650.
@article{osti_1435650,
title = {Quasistationary Plasma Predator-Prey System of Coupled Turbulence, Drive, and Sheared E×B Flow During High Performance DIII-D Tokamak Discharges [A New, Quasi-stationary Plasma Predator-Prey System of Coupled Turbulence, Drive, and Sheared E×B Flow During High Performance DIII-D Tokamak Discharges]},
author = {Barada, Kshitish and Rhodes, Terry L. and Burrell, Keith H. and Zeng, L. and Bardoczi, Laszlo and Chen, Xi and Muscatello, Christopher M. and Peebles, W. A.},
abstractNote = {A new, long-lived limit cycle oscillation (LCO) regime has been observed in the edge of near zero torque high-performance DIII-D tokamak plasma discharges. These LCOs are localized and comprised of density turbulence, gradient drives, and E X B velocity shear damping (E and B are the local radial electric and total magnetic fields). Density turbulence sequentially acts as a predator (via turbulence transport) of profile gradients and a prey (via shear suppression) to the E X B velocity shear. Reported here for the first time, a unique spatiotemporal variation of the local E X B velocity which is found to be essential for the existence of this system. The LCO system is quasi-stationary, existing from 3 to 12 plasma energy confinement times (~30 to 900 LCO cycles) limited by hardware constraints. In conclusion, this plasma system appears to contribute strongly to the edge transport in these high-performance and transient-free plasmas as evident from oscillations in transport relevant edge parameters at LCO timescale.},
doi = {10.1103/PhysRevLett.120.135002},
journal = {Physical Review Letters},
number = 13,
volume = 120,
place = {United States},
year = {Tue Mar 27 00:00:00 EDT 2018},
month = {Tue Mar 27 00:00:00 EDT 2018}
}

Journal Article:

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Cited by: 7 works
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Figures / Tables:

Fig. 1. Fig. 1. : (a) NBI power and torque, (b) n=1 EHO amplitude as measured by Mirnov coils and chord averaged electron density, (c) Electron pedestal pressure width and electron pedestal pressure. Shown are the wide pedestal transition (solid line ~2385 ms) and EHO to LCO regime transition (dashed line ~3257ms).

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Works referencing / citing this record:

An experimental investigation of blob behaviors in lower hybrid wave dominant heating scenarios on EAST
journal, July 2019

  • Wang, Q.; Hu, G. H.; Sheng, Z. M.
  • Physics of Plasmas, Vol. 26, Issue 7
  • DOI: 10.1063/1.5093790

Long-lived predator-prey dynamics in the pedestal of near-zero torque high performance DIII-D plasmas
journal, September 2019

  • Barada, K.; Rhodes, T. L.; Burrell, K. H.
  • Physics of Plasmas, Vol. 26, Issue 9
  • DOI: 10.1063/1.5097143

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