English

Bifurcations of the magnetic axis and the alternating-hyperbolic sawtooth

Plasma Physics 2020-07-10 v1

Abstract

We present a sawtooth model that explains observations where the central safety factor, q0q_0, stays well below one, which is irreconcilable with current models that predict a reset to q0=1q_0=1 after the crash. We identify the structure of the field around the magnetic axis with elements of the Lie group SL(2,R)\mathrm{SL}(2,\mathbb{R}) and find a transition to an alternating-hyperbolic geometry when q0=2/3q_0=2/3. This transition is driven by an ideal MHD instability and leads to a chaotic magnetic field near the axis.

Keywords

Cite

@article{arxiv.2007.04529,
  title  = {Bifurcations of the magnetic axis and the alternating-hyperbolic sawtooth},
  author = {C. B. Smiet and G. J. Kramer and S. R. Hudson},
  journal= {arXiv preprint arXiv:2007.04529},
  year   = {2020}
}