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

This content will become publicly available on February 20, 2021

Title: A new mechanism for filament disconnection at the X-point: poloidal shear in radial E × B velocity

Abstract

Plasma filaments generated by turbulence in the scrape-off layer are sometimes observed in experiments and simulations to disconnect from the target plate in the vicinity of the X-point, resulting in a ‘quiescent zone’ with reduced fluctuations, possibly affecting the fluctuating part of the divertor heat loads. This phenomena is usually explained by the flux tubes squeezing, induced by flux expansion, down to scales where collisions dominate. In this work, we consider an additional mechanism spontaneously arising at the X-point: the poloidal shear in radial E × B velocity. Through a simple model, tested against 3D global turbulence simulations, herein we quantify the effectiveness of this disconnection mechanism and identify ways to control it.

Authors:
ORCiD logo [1];  [2]; ORCiD logo [2];  [3];  [4]
  1. Princeton Plasma Physics Lab. (PPPL), Princeton, NJ (United States)
  2. CEA Cadarache, St. Paul-lez-Durance (France). IRFM
  3. École Polytechnique Fédérale de Lausanne (EPFL) (Switzerland). Swiss Plasma Center (SPC)
  4. Aix Marseille Univ. (France)
Publication Date:
Research Org.:
Princeton Plasma Physics Lab. (PPPL), Princeton, NJ (United States)
Sponsoring Org.:
USDOE; European Commission (EC)
OSTI Identifier:
1595813
Grant/Contract Number:  
AC02-09CH11466; 633053
Resource Type:
Accepted Manuscript
Journal Name:
Nuclear Fusion
Additional Journal Information:
Journal Volume: 60; Journal Issue: 4; Journal ID: ISSN 0029-5515
Publisher:
IOP Science
Country of Publication:
United States
Language:
English
Subject:
70 PLASMA PHYSICS AND FUSION TECHNOLOGY; turbulence; sheared flow; plasma filaments

Citation Formats

Nespoli, Federico, Tamain, Patrick, Fedorczak, Nicolas, Galassi, Davide, and Marandet, Yannick. A new mechanism for filament disconnection at the X-point: poloidal shear in radial E × B velocity. United States: N. p., 2020. Web. doi:10.1088/1741-4326/ab6f1e.
Nespoli, Federico, Tamain, Patrick, Fedorczak, Nicolas, Galassi, Davide, & Marandet, Yannick. A new mechanism for filament disconnection at the X-point: poloidal shear in radial E × B velocity. United States. doi:10.1088/1741-4326/ab6f1e.
Nespoli, Federico, Tamain, Patrick, Fedorczak, Nicolas, Galassi, Davide, and Marandet, Yannick. Thu . "A new mechanism for filament disconnection at the X-point: poloidal shear in radial E × B velocity". United States. doi:10.1088/1741-4326/ab6f1e.
@article{osti_1595813,
title = {A new mechanism for filament disconnection at the X-point: poloidal shear in radial E × B velocity},
author = {Nespoli, Federico and Tamain, Patrick and Fedorczak, Nicolas and Galassi, Davide and Marandet, Yannick},
abstractNote = {Plasma filaments generated by turbulence in the scrape-off layer are sometimes observed in experiments and simulations to disconnect from the target plate in the vicinity of the X-point, resulting in a ‘quiescent zone’ with reduced fluctuations, possibly affecting the fluctuating part of the divertor heat loads. This phenomena is usually explained by the flux tubes squeezing, induced by flux expansion, down to scales where collisions dominate. In this work, we consider an additional mechanism spontaneously arising at the X-point: the poloidal shear in radial E × B velocity. Through a simple model, tested against 3D global turbulence simulations, herein we quantify the effectiveness of this disconnection mechanism and identify ways to control it.},
doi = {10.1088/1741-4326/ab6f1e},
journal = {Nuclear Fusion},
number = 4,
volume = 60,
place = {United States},
year = {2020},
month = {2}
}

Journal Article:
Free Publicly Available Full Text
This content will become publicly available on February 20, 2021
Publisher's Version of Record

Save / Share:

Works referenced in this record:

On heat loading, novel divertors, and fusion reactors
journal, July 2007

  • Kotschenreuther, M.; Valanju, P. M.; Mahajan, S. M.
  • Physics of Plasmas, Vol. 14, Issue 7
  • DOI: 10.1063/1.2739422

Penetration of filamentary structures into the divertor region of spherical tokamaks
journal, February 2019

  • Baver, D. A.; Myra, J. R.
  • Physics of Plasmas, Vol. 26, Issue 2
  • DOI: 10.1063/1.5065390

Width of turbulent SOL in circular plasmas: A theoretical model validated on experiments in Tore Supra tokamak
journal, August 2017


Drive of parallel flows by turbulence and large-scale E × B transverse transport in divertor geometry
journal, February 2017


Effect of the magnetic field geometry on the flute-like perturbations near the divertor X point
journal, September 1993


Tokamak Edge Plasma Turbulence Interaction with Magnetic X-Point in 3D Global Simulations
journal, March 2019


Experimental Validation of a Filament Transport Model in Turbulent Magnetized Plasmas
journal, November 2015


The snowflake divertor
journal, November 2015

  • Ryutov, D. D.; Soukhanovskii, V. A.
  • Physics of Plasmas, Vol. 22, Issue 11
  • DOI: 10.1063/1.4935115

Simulation of turbulence in the divertor region of tokamak edge plasma
journal, March 2005


Edge and SOL turbulence and blob variations over a large database in NSTX
journal, September 2015


Transport by intermittent convection in the boundary of the DIII-D tokamak
journal, November 2001

  • Boedo, J. A.; Rudakov, D.; Moyer, R.
  • Physics of Plasmas, Vol. 8, Issue 11
  • DOI: 10.1063/1.1406940

Filamentary velocity scaling validation in the TCV tokamak
journal, July 2018

  • Tsui, C. K.; Boedo, J. A.; Myra, J. R.
  • Physics of Plasmas, Vol. 25, Issue 7
  • DOI: 10.1063/1.5038019

The TOKAM3X code for edge turbulence fluid simulations of tokamak plasmas in versatile magnetic geometries
journal, September 2016


Divertor leg filaments in NSTX-U
journal, October 2018


Disconnection of scrape off layer turbulence between the outer midplane and divertor target plate in NSTX
journal, December 2019


The super X divertor (SXD) and a compact fusion neutron source (CFNS)
journal, February 2010


3D structure and dynamics of filaments in turbulence simulations of WEST diverted plasmas
journal, July 2019


Recent theoretical progress in understanding coherent structures in edge and SOL turbulence
journal, October 2008

  • Krasheninnikov, S. I.; D'Ippolito, D. A.; Myra, J. R.
  • Journal of Plasma Physics, Vol. 74, Issue 5
  • DOI: 10.1017/S0022377807006940