Wednesday 16 Oct 2013: (CHANGE OF TIME) Influence of rotation rate, magnetic field topology and strength on magnetic braking for sun-like stars (short talk)
Victor Reville - CEA/Irfu Universite Paris-Diderot CNRS/INSU, France
Physics, 4th floor 13:30-14:15
Angular momentum loss through stellar winds is known for playing an important role in main-sequence stars spin down. We use 2D, axisymmetric MHD simulations with the PLUTO code (Mignone 2007) to quantify stellar wind torques. Extending a previous study made in Matt et. al. 2012 that considered only a dipole magnetic field, we quantify the influence of the magnetic topology on the magnetic braking. In addition to a dipole field, two new initial topologies are introduced, a quadrupole and an octupole, while we also vary the rotation rate and the magnetic field strength. We attempt to derive a formula for the torque that includes the topology, through a filling-factor quantifying the open flux carrying the wind.