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

Nespoli, Federico; Tamain, Patrick; Fedorczak, Nicolas; Galassi, Davide; Marandet, Yannick

doi:10.1088/1741-4326/ab6f1e

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:

^[1]; Tamain, Patrick ^[2];

^[2]; Galassi, Davide ^[3]; Marandet, Yannick ^[4]

Princeton Plasma Physics Lab. (PPPL), Princeton, NJ (United States)
CEA Cadarache, St. Paul-lez-Durance (France). IRFM
École Polytechnique Fédérale de Lausanne (EPFL) (Switzerland). Swiss Plasma Center (SPC)
Aix Marseille Univ. (France)

Publication Date:: Thu Feb 20 00:00:00 EST 2020

Research Org.:: Princeton Plasma Physics Laboratory (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.

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                    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.  https://doi.org/10.1088/1741-4326/ab6f1e

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                    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.  https://doi.org/10.1088/1741-4326/ab6f1e.  https://www.osti.gov/servlets/purl/1595813.

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@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         = {Thu Feb 20 00:00:00 EST 2020},

  month        = {Thu Feb 20 00:00:00 EST 2020}

}

Copy to clipboard

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Works referenced in this record:

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Similar Records

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

Abstract

Citation Formats

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

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

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

A study of the perpendicular particle transport properties in the scrape-off layer of ASDEX journal, May 1985

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

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

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

Intermittent divertor filaments in the National Spherical Torus Experiment and their relation to midplane blobs journal, June 2010

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

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

Quiescence near the X-point of MAST measured by high speed visible imaging text, January 2017

Penetration Of Filamentary Structures Into The Divertor Region Of Spherical Tokamaks text, January 2018

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

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

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

A study of the perpendicular particle transport properties in the scrape-off layer of ASDEX
journal, May 1985

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

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

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

Intermittent divertor filaments in the National Spherical Torus Experiment and their relation to midplane blobs
journal, June 2010

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

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

Quiescence near the X-point of MAST measured by high speed visible imaging
text, January 2017

Penetration Of Filamentary Structures Into The Divertor Region Of Spherical Tokamaks
text, January 2018