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 September 3, 2020

Title: Three-dimensional plasmoid-mediated reconnection and the effect of toroidal guide field in simulations of coaxial helicity injection

Abstract

Physics of three-dimensional plasmoid-mediated magnetic reconnection during transient Coaxial Helicity Injection (CHI) plasma start-up is explored using nonlinear MHD simulations in a spherical tokamak. We numerically examine (i) the role of three-dimensional magnetic fluctuations arising from current-sheet instabilities on the formation of plasmoid-mediated closed flux surfaces, and (ii) the effect of toroidal guide field on the MHD stability during transient CHI. We find that even in the presence of nonaxisymmetric edge magnetic fluctuations, current-carrying axisymmetric (n¼0) plasmoids are rapidly formed while twisted open field lines are being injected and are merged to form a large current-carrying magnetic bubble for plasma startup in a tokamak. Additionally, it is discovered that the 3-D physics response is drastically different for simulations at a higher toroidal field, and complete stabilization of nonaxisymmetric fluctuations was achieved at a higher toroidal flux.

Authors:
Publication Date:
Research Org.:
Lawrence Berkeley National Laboratory (LBNL), Berkeley, CA (United States). National Energy Research Scientific Computing Center (NERSC); Princeton Univ., NJ (United States)
Sponsoring Org.:
USDOE Office of Science (SC)
OSTI Identifier:
1577594
Alternate Identifier(s):
OSTI ID: 1560254
Grant/Contract Number:  
AC02-09CH11466; SC0010565
Resource Type:
Accepted Manuscript
Journal Name:
Physics of Plasmas
Additional Journal Information:
Journal Volume: 26; Journal Issue: 9; Journal ID: ISSN 1070-664X
Publisher:
American Institute of Physics (AIP)
Country of Publication:
United States
Language:
English
Subject:
70 PLASMA PHYSICS AND FUSION TECHNOLOGY

Citation Formats

None, None. Three-dimensional plasmoid-mediated reconnection and the effect of toroidal guide field in simulations of coaxial helicity injection. United States: N. p., 2019. Web. doi:10.1063/1.5098482.
None, None. Three-dimensional plasmoid-mediated reconnection and the effect of toroidal guide field in simulations of coaxial helicity injection. United States. doi:10.1063/1.5098482.
None, None. Tue . "Three-dimensional plasmoid-mediated reconnection and the effect of toroidal guide field in simulations of coaxial helicity injection". United States. doi:10.1063/1.5098482.
@article{osti_1577594,
title = {Three-dimensional plasmoid-mediated reconnection and the effect of toroidal guide field in simulations of coaxial helicity injection},
author = {None, None},
abstractNote = {Physics of three-dimensional plasmoid-mediated magnetic reconnection during transient Coaxial Helicity Injection (CHI) plasma start-up is explored using nonlinear MHD simulations in a spherical tokamak. We numerically examine (i) the role of three-dimensional magnetic fluctuations arising from current-sheet instabilities on the formation of plasmoid-mediated closed flux surfaces, and (ii) the effect of toroidal guide field on the MHD stability during transient CHI. We find that even in the presence of nonaxisymmetric edge magnetic fluctuations, current-carrying axisymmetric (n¼0) plasmoids are rapidly formed while twisted open field lines are being injected and are merged to form a large current-carrying magnetic bubble for plasma startup in a tokamak. Additionally, it is discovered that the 3-D physics response is drastically different for simulations at a higher toroidal field, and complete stabilization of nonaxisymmetric fluctuations was achieved at a higher toroidal flux.},
doi = {10.1063/1.5098482},
journal = {Physics of Plasmas},
number = 9,
volume = 26,
place = {United States},
year = {2019},
month = {9}
}

Journal Article:
Free Publicly Available Full Text
This content will become publicly available on September 3, 2020
Publisher's Version of Record

Save / Share:

Works referenced in this record:

The three-dimensional magnetohydrodynamics of ac helicity injection in the reversed field pinch
journal, April 2003

  • Ebrahimi, F.; Prager, S. C.; Sarff, J. S.
  • Physics of Plasmas, Vol. 10, Issue 4
  • DOI: 10.1063/1.1555622

Equilibrium evolution in oscillating-field current-drive experiments
journal, August 2010

  • McCollam, K. J.; Anderson, J. K.; Blair, A. P.
  • Physics of Plasmas, Vol. 17, Issue 8
  • DOI: 10.1063/1.3461167

Plasmoids Formation During Simulations of Coaxial Helicity Injection in the National Spherical Torus Experiment
journal, May 2015


General theory of the plasmoid instability
journal, October 2016

  • Comisso, L.; Lingam, M.; Huang, Y. -M.
  • Physics of Plasmas, Vol. 23, Issue 10
  • DOI: 10.1063/1.4964481

Nonlinear magnetohydrodynamics simulation using high-order finite elements
journal, March 2004

  • Sovinec, C. R.; Glasser, A. H.; Gianakon, T. A.
  • Journal of Computational Physics, Vol. 195, Issue 1
  • DOI: 10.1016/j.jcp.2003.10.004

The topological properties of magnetic helicity
journal, October 1984


Tokamak startup using outboard current injection on the Pegasus Toroidal Experiment
journal, June 2011


Application of transient CHI plasma startup to future ST and AT devices
journal, March 2019

  • Hammond, K. C.; Raman, R.; Jardin, S. C.
  • Physics of Plasmas, Vol. 26, Issue 3
  • DOI: 10.1063/1.5087259

Demonstration of Tokamak Ohmic Flux Saving by Transient Coaxial Helicity Injection in the National Spherical Torus Experiment
journal, March 2010


Formation and Steady-State Sustainment of a Tokamak by Coaxial Helicity Injection
journal, January 1989


Nonlinear reconnecting edge localized modes in current-carrying plasmas
journal, May 2017


Magnetic Helicity and Large Scale Magnetic Fields: A Primer
journal, April 2014


Slow Formation and Sustainment of Spheromaks by a Coaxial Magnetized Plasma Source
journal, July 1983


Demonstration of Plasma Startup by Coaxial Helicity Injection
journal, February 2003


Phase diagram for magnetic reconnection in heliophysical, astrophysical, and laboratory plasmas
journal, November 2011

  • Ji, Hantao; Daughton, William
  • Physics of Plasmas, Vol. 18, Issue 11
  • DOI: 10.1063/1.3647505

Self-organization during spherical torus formation by flux rope merging in the Mega Ampere Spherical Tokamak
journal, April 2014


Magnetic reconnection via current sheets
journal, January 1986


Measurement of Magnetic Helicity Injection and Free Energy Loading into the Solar Corona
journal, September 2002

  • Kusano, K.; Maeshiro, T.; Yokoyama, T.
  • The Astrophysical Journal, Vol. 577, Issue 1
  • DOI: 10.1086/342171

Efficient Generation of Closed Magnetic Flux Surfaces in a Large Spherical Tokamak Using Coaxial Helicity Injection
journal, October 2006


A current-driven resistive instability and its nonlinear effects in simulations of coaxial helicity injection in a tokamak
journal, October 2016

  • Hooper, E. B.; Sovinec, C. R.
  • Physics of Plasmas, Vol. 23, Issue 10
  • DOI: 10.1063/1.4964292

Resistive magnetohydrodynamic simulations of helicity-injected startup plasmas in National Spherical Torus eXperiment
journal, September 2013

  • Hooper, E. B.; Sovinec, C. R.; Raman, R.
  • Physics of Plasmas, Vol. 20, Issue 9
  • DOI: 10.1063/1.4821977

Exploration of spherical torus physics in the NSTX device
journal, March 2000


Dynamo-driven plasmoid formation from a current-sheet instability
journal, December 2016


Modelling and observations of photospheric magnetic helicity
journal, April 2009


Magnetic reconnection process in transient coaxial helicity injection
journal, September 2013

  • Ebrahimi, F.; Hooper, E. B.; Sovinec, C. R.
  • Physics of Plasmas, Vol. 20, Issue 9
  • DOI: 10.1063/1.4821974

Physics of forced magnetic reconnection in coaxial helicity injection experiments in National Spherical Torus Experiment
journal, May 2014

  • Ebrahimi, F.; Raman, R.; Hooper, E. B.
  • Physics of Plasmas, Vol. 21, Issue 5
  • DOI: 10.1063/1.4875337

Large-volume flux closure during plasmoid-mediated reconnection in coaxial helicity injection
journal, March 2016


Instability of current sheets and formation of plasmoid chains
journal, October 2007

  • Loureiro, N. F.; Schekochihin, A. A.; Cowley, S. C.
  • Physics of Plasmas, Vol. 14, Issue 10
  • DOI: 10.1063/1.2783986

Initial results from solenoid-free plasma start-up using Transient CHI on QUEST
journal, September 2018

  • Kuroda, K.; Raman, R.; Hanada, K.
  • Plasma Physics and Controlled Fusion, Vol. 60, Issue 11
  • DOI: 10.1088/1361-6587/aadcb7

The role of the nϕ=1 column mode in spheromak formation
journal, April 2009

  • Cohen, B. I.; Romero-Talamás, C. A.; Ryutov, D. D.
  • Physics of Plasmas, Vol. 16, Issue 4
  • DOI: 10.1063/1.3097909

Transition from collisional to kinetic regimes in large-scale reconnection layers
journal, August 2009