Properties of r modes in rotating magnetic neutron stars. II. Evolution ofthe r modes and stellar magnetic field - art. no. 104014

The evolution of the r-mode instability is likely, to be accompanied by sec ular kinematic effects which will produce differential rotation with large scale drifts. of fluid elements, mostly in the azimuthal direction. As prev iously discussed, the interaction of these secular velocity fields with a p reexisting neutron star magnetic field could result in the generation of in tense and, large scale toroidal fields. Following their derivation in the p receding paper, here we discuss a numerical solution of the evolution equat ions for the magnetic field. The values of the magnetic fields. obtained in this way are used to estimate the conditions under which the r-mode instab ility might be prevented or suppressed. We also assess the impact of the ge neration of large magnetic fields on the gravitational wave detectability o f r-mode unstable neutron stars. Our results indicate that the signal to no ise ratio in the detection of gravitational waves from the r-mode instabili ty might be considerably decreased if the latter develops in neutron stars with initial magnetic fields larger than 10(10) G.