Amplification of azimuthal modes with odd wave numbers during dynamical bar-mode growth in rotating stars

Abstract

Nonlinear growth of the bar-mode deformation is studied for a differentially rotating star with supercritical rotational energy. In particular, the growth mechanism of some azimuthal modes with odd wave numbers is examined by comparing a simplified mathematical model with a realistic simulation. Mode coupling to even modes, i.e., the bar mode and higher harmonics, significantly enhances the amplitudes of odd modes, unless they are exactly zero initially. Therefore, other modes which are not axially symmetric cannot be neglected at late times in the growth of the unstable bar-mode even when starting from an almost axially symmetric state.

10 pages with 5 figures, revtex4.cls. Accepted for publication in the Physical Review D

References in corpus (4)

• Accurate simulations of the dynamical bar-mode instability in full General Relativity
• Unexpected Dynamical Instabilities In Differentially Rotating Neutron Stars
• AMR simulations of the low T/|W| bar-mode instability of neutron stars
• Faraday resonance in dynamical bar instability of differentially rotating stars