Helical Magnetorotational Instability in Magnetized Taylor-Couette Flow

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dc.creatorLiu, Wei
dc.creatorGoodman, Jeremy
dc.creatorHerron, Isom
dc.creatorJi, Hantao
dc.date2006-06-06
dc.date.accessioned2026-07-07T10:23:10Z
dc.date.available2026-07-07T10:23:10Z
dc.descriptionHollerbach and Rudiger have reported a new type of magnetorotational instability (MRI) in magnetized Taylor-Couette flow in the presence of combined axial and azimuthal magnetic fields. The salient advantage of this "helical'' MRI (HMRI) is that marginal instability occurs at arbitrarily low magnetic Reynolds and Lundquist numbers, suggesting that HMRI might be easier to realize than standard MRI (axial field only). We confirm their results, calculate HMRI growth rates, and show that in the resistive limit, HMRI is a weakly destabilized inertial oscillation propagating in a unique direction along the axis. But we report other features of HMRI that make it less attractive for experiments and for resistive astrophysical disks. Growth rates are small and require large axial currents. More fundamentally, instability of highly resistive flow is peculiar to infinitely long or periodic cylinders: finite cylinders with insulating endcaps are shown to be stable in this limit. Also, keplerian rotation profiles are stable in the resistive limit regardless of axial boundary conditions. Nevertheless, the addition of toroidal field lowers thresholds for instability even in finite cylinders.
dc.description16 pages, 2 figures, 1 table, submitted to PRE
dc.identifierhttps://arxiv.org/abs/astro-ph/0606125
dc.identifierhttp://arxiv.org/abs/astro-ph/0606125
dc.identifierPhys.Rev.E74:056302,2006
dc.identifierdoi:10.1103/PhysRevE.74.056302
dc.identifier.urihttp://salesiana.dossiersoluciones.com/handle/123456789/175730
dc.subjectAstrophysics
dc.subjectFluid Dynamics
dc.titleHelical Magnetorotational Instability in Magnetized Taylor-Couette Flow
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