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Title: Topological bifurcation of magnetic islands in NSTX-U

Abstract

The topological bifurcation of magnetic islands is observed in two M3D-C1 linear resistive MHD calculations of model NSTX-U equilibria during the application of small 3D magnetic perturbation fields. In comparing to a DIII-D ELM suppression case, reconstructed from shot 147170 at time slice 3745 ms, we propose that stronger kink response in the NSTX-U plasma may be the primary causes of the bifurcations. Island evolution and bifurcation in both the DIII-D and the two NSTX-U cases with the increase of perturbation current are analyzed. Further, a hypothesis is proposed that such magnetic island topology bears an intrinsic property to confine charged particles and cause their density inside the islands to rise, which is examined by implementing a random kick algorithm in the magnetic field line integration code TRIP3D-GPU to approximate electron collisional transport. Although full consideration of all forces between electrons is missing as it requires 3D large scale kinetic simulation in toroidal geometry, the positive result of this approximate transport simulation does provide first step confirmation towards fully validating the hypothesis.

Authors:
 [1]; ORCiD logo [1];  [2];  [3]; ORCiD logo [1]; ORCiD logo [4]
  1. General Atomics, San Diego, CA (United States)
  2. Dept. of Applied Physics, University of Sao Paulo, Sao Paulo, (Brazil)
  3. Princeton Plasma Physics Laboratory, Princeton, NJ (United States)
  4. Univ. of California San DiegoLa Jolla, CA (United States. Center for Energy Research
Publication Date:
Research Org.:
Princeton Plasma Physics Lab. (PPPL), Princeton, NJ (United States); U.S. Dept. of Energy (USDOE), Washington DC (United States)
Sponsoring Org.:
USDOE Office of Science (SC), Fusion Energy Sciences (FES) (SC-24)
OSTI Identifier:
1559882
Alternate Identifier(s):
OSTI ID: 1569692
Grant/Contract Number:  
AC02-09CH114663; AC05-06OR231002; FC02-04ER54698; FG02-95ER54309; SC0012706; SC0018030; DEFG02-05ER54809
Resource Type:
Accepted Manuscript
Journal Name:
Nuclear Fusion
Additional Journal Information:
Journal Volume: 59; Journal Issue: 6; Journal ID: ISSN 0029-5515
Publisher:
IOP Science
Country of Publication:
United States
Language:
English
Subject:
70 PLASMA PHYSICS AND FUSION TECHNOLOGY

Citation Formats

Wu, W., Evans, T. E., Canal, G. P., Ferraro, N. M., Lyons, B. C., and Orlov, D. M. Topological bifurcation of magnetic islands in NSTX-U. United States: N. p., 2019. Web. doi:10.1088/1741-4326/ab127e.
Wu, W., Evans, T. E., Canal, G. P., Ferraro, N. M., Lyons, B. C., & Orlov, D. M. Topological bifurcation of magnetic islands in NSTX-U. United States. doi:10.1088/1741-4326/ab127e.
Wu, W., Evans, T. E., Canal, G. P., Ferraro, N. M., Lyons, B. C., and Orlov, D. M. Fri . "Topological bifurcation of magnetic islands in NSTX-U". United States. doi:10.1088/1741-4326/ab127e.
@article{osti_1559882,
title = {Topological bifurcation of magnetic islands in NSTX-U},
author = {Wu, W. and Evans, T. E. and Canal, G. P. and Ferraro, N. M. and Lyons, B. C. and Orlov, D. M.},
abstractNote = {The topological bifurcation of magnetic islands is observed in two M3D-C1 linear resistive MHD calculations of model NSTX-U equilibria during the application of small 3D magnetic perturbation fields. In comparing to a DIII-D ELM suppression case, reconstructed from shot 147170 at time slice 3745 ms, we propose that stronger kink response in the NSTX-U plasma may be the primary causes of the bifurcations. Island evolution and bifurcation in both the DIII-D and the two NSTX-U cases with the increase of perturbation current are analyzed. Further, a hypothesis is proposed that such magnetic island topology bears an intrinsic property to confine charged particles and cause their density inside the islands to rise, which is examined by implementing a random kick algorithm in the magnetic field line integration code TRIP3D-GPU to approximate electron collisional transport. Although full consideration of all forces between electrons is missing as it requires 3D large scale kinetic simulation in toroidal geometry, the positive result of this approximate transport simulation does provide first step confirmation towards fully validating the hypothesis.},
doi = {10.1088/1741-4326/ab127e},
journal = {Nuclear Fusion},
number = 6,
volume = 59,
place = {United States},
year = {2019},
month = {4}
}

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