Analysis of the Helical Kink Stability of Differently Twisted Magnetic Flux Ropes. (arXiv:2007.06345v2 [astro-ph.SR] UPDATED)
<a href="http://arxiv.org/find/astro-ph/1/au:+Florido_Llinas_M/0/1/0/all/0/1">Marta Florido-Llinas</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Nieves_Chinchilla_T/0/1/0/all/0/1">Teresa Nieves-Chinchilla</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Linton_M/0/1/0/all/0/1">Mark G. Linton</a>
Magnetic flux ropes (MFRs) are usually considered to be the magnetic
structure that dominates the transport of helicity from the Sun into the
heliosphere. They entrain a confined plasma within a helically organized
magnetic structure and are able to cause geomagnetic activity. The formation,
evolution and twist distribution of MFRs are issues subject to strong debate.
Although different twist profiles have been suggested so far, none of them has
been thoroughly explored yet. The aim of this work is to present a theoretical
study of the conditions under which MFRs with different twist profiles are kink
stable and thereby shed some light on the aforementioned aspects. The magnetic
field is modeled according to the circular-cylindrical analytical flux rope
model in Nieves-Chinchilla et al. (Astrophys. J. 823, 27, 2016) as well as the
Lundquist and Gold-Hoyle models, and the kink stability is analyzed with a
numerical method that has been developed based on Linton, Longcope, and Fisher
(Astrophys. J. 469, 954, 1996). The results are discussed in relation to MFR
rotations, magnetic forces, the reversed chirality scenario, and the expansion
throughout the heliosphere, among others, providing a theoretical background to
improve the current understanding of the internal magnetic configuration of
coronal mass ejections (CMEs). The data obtained by new missions like Parker
Solar Probe or Solar Orbiter will give the opportunity to explore these results
and ideas by observing MFRs closer than ever to the Sun.
Magnetic flux ropes (MFRs) are usually considered to be the magnetic
structure that dominates the transport of helicity from the Sun into the
heliosphere. They entrain a confined plasma within a helically organized
magnetic structure and are able to cause geomagnetic activity. The formation,
evolution and twist distribution of MFRs are issues subject to strong debate.
Although different twist profiles have been suggested so far, none of them has
been thoroughly explored yet. The aim of this work is to present a theoretical
study of the conditions under which MFRs with different twist profiles are kink
stable and thereby shed some light on the aforementioned aspects. The magnetic
field is modeled according to the circular-cylindrical analytical flux rope
model in Nieves-Chinchilla et al. (Astrophys. J. 823, 27, 2016) as well as the
Lundquist and Gold-Hoyle models, and the kink stability is analyzed with a
numerical method that has been developed based on Linton, Longcope, and Fisher
(Astrophys. J. 469, 954, 1996). The results are discussed in relation to MFR
rotations, magnetic forces, the reversed chirality scenario, and the expansion
throughout the heliosphere, among others, providing a theoretical background to
improve the current understanding of the internal magnetic configuration of
coronal mass ejections (CMEs). The data obtained by new missions like Parker
Solar Probe or Solar Orbiter will give the opportunity to explore these results
and ideas by observing MFRs closer than ever to the Sun.
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