Mapping the sawtooth
Abstract
The sawtooth oscillation involves a topological change of the magnetic field lines in the core of a tokamak discharge. In this work, we simulate a steady state sawtoothing discharge using the M3DC ^{1}code. During the sawtooth the topological structure of the magnetic field is analyzed by tracking the fixed points of the field line map: the mapping induced by the field lines going once around the tokamak. We numerically locate the fixed points of the field line map (of which the magnetic axis is one) and use them construct a Poincaré section that resolves the core region and the (1, 1) island. Finally, by following the evolution of the magnetic field through the motion and bifurcation of the fixed points of the field line map we get an intuitive picture of the processes that take place during a Kadomtsev style sawtooth crash.
 Authors:

 Princeton Plasma Physics Lab. (PPPL), Princeton, NJ (United States); Leiden Univ. (Netherlands)
 Princeton Plasma Physics Lab. (PPPL), Princeton, NJ (United States)
 Publication Date:
 Research Org.:
 Princeton Plasma Physics Lab. (PPPL), Princeton, NJ (United States)
 Sponsoring Org.:
 USDOE Office of Science (SC), Fusion Energy Sciences (FES)
 OSTI Identifier:
 1580273
 Grant/Contract Number:
 AC0209CH11466
 Resource Type:
 Accepted Manuscript
 Journal Name:
 Plasma Physics and Controlled Fusion
 Additional Journal Information:
 Journal Volume: 62; Journal Issue: 2; Journal ID: ISSN 07413335
 Publisher:
 IOP Science
 Country of Publication:
 United States
 Language:
 English
 Subject:
 70 PLASMA PHYSICS AND FUSION TECHNOLOGY
Citation Formats
Smiet, C. B., Kramer, G. J., and Hudson, S. R. Mapping the sawtooth. United States: N. p., 2019.
Web. doi:10.1088/13616587/ab5073.
Smiet, C. B., Kramer, G. J., & Hudson, S. R. Mapping the sawtooth. United States. doi:10.1088/13616587/ab5073.
Smiet, C. B., Kramer, G. J., and Hudson, S. R. Wed .
"Mapping the sawtooth". United States. doi:10.1088/13616587/ab5073. https://www.osti.gov/servlets/purl/1580273.
@article{osti_1580273,
title = {Mapping the sawtooth},
author = {Smiet, C. B. and Kramer, G. J. and Hudson, S. R.},
abstractNote = {The sawtooth oscillation involves a topological change of the magnetic field lines in the core of a tokamak discharge. In this work, we simulate a steady state sawtoothing discharge using the M3DC 1code. During the sawtooth the topological structure of the magnetic field is analyzed by tracking the fixed points of the field line map: the mapping induced by the field lines going once around the tokamak. We numerically locate the fixed points of the field line map (of which the magnetic axis is one) and use them construct a Poincaré section that resolves the core region and the (1, 1) island. Finally, by following the evolution of the magnetic field through the motion and bifurcation of the fixed points of the field line map we get an intuitive picture of the processes that take place during a Kadomtsev style sawtooth crash.},
doi = {10.1088/13616587/ab5073},
journal = {Plasma Physics and Controlled Fusion},
number = 2,
volume = 62,
place = {United States},
year = {2019},
month = {10}
}
Web of Science
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