Nonlinear r-modes in neutron stars: A hydrodynamical limitation on r-mode amplitudes

Abstract

Previously we found that large amplitude $r$-modes could decay catastrophically due to nonlinear hydrodynamic effects. In this paper we found the particular coupling mechanism responsible for this catastrophic decay, and identified the fluid modes involved. We find that for a neutron star described by a polytropic equation of state with polytropic index $\Gamma =2$, the coupling strength of the particular three-mode interaction causing the decay is strong enough that the usual picture of the $r$-mode instability with a flow pattern dominated by that of an $r$-mode can only be valid for the dimensionless $r$-mode amplitude less than $O(10^{-2})$.

arXiv commentAn extended version with the eigenfunctions of the coupled modes extracted. Version accepted for publication in MNRAS

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Cited by in corpus (10)

• Rotating Stars in Relativity
• Large amplitude behavior of the bulk viscosity of dense matter
• Viscous damping of r-modes: Large amplitude saturation
• Gravitational wave emission from oscillating millisecond pulsars
• Stochastic Gravitational Wave Background from Neutron Star r-mode Instability Revisited
• On the saturation amplitude of the f-mode instability
• Nonlinear radial oscillations of neutron stars
• Inertial modes of rigidly rotating neutron stars in Cowling approximation
• Shear viscosity and the r-mode instability window in superfluid neutron stars
• Nonlinear Decay of r modes in Rapidly Rotating Neutron Stars