Talk detail

Participant	Saijo, Motoyuki
Institution	Rikkyo University - 3-34-1 Nishi Ikebukuro, Toshima - Tokyo - - Japan

Session	SN3	Accepted	Yes	Order	8	Time	20'
Talk	Oral abstract	Title	Nonlinear effect of r-mode instability in uniformly rotating stars
Co-authors
Abstract	We investigate the r-mode instability of uniformly rotating stars by means of three dimensional hydrodynamical simulations in Newtonian gravity with radiation reaction effect. We propose a nonlinear anelastic approximation in the corotating frame, which kills the propagation of sound speed, in order to evolve the system beyond the dynamical timescale. We have succeeded in evolving uniformly rotating stars up to at least around several hundred rotation period with our new scheme, which is at least 10 times longer than the previous standard hydrodynamical simulations. In order to verify our developed code, we impose the harmonic index of l=m=2 perturbation of an incompressible unstable r-mode eigenfunction to the equilibrium velocity, and find that the characteristic frequency of the unstable r-mode is excited throughout the evolution. We discuss the features of nonlinear r-mode instability with our newly developed code, such as saturation amplitude of its instability.