Magnetohydrodynamic Simulations of Stellar Magnetosphere-Accretion Disk Interaction

摘要: The magnetohydrodynamic evolution of the interaction region between inner edge an accretion disk and magnetosphere central object is studied by means time-dependent numerical simulations. simulations assume adiabatic, axisymmetric, has nonzero resistivity, initially in Keplerian rotation. assumed to be magnetostatic equilibrium, corotating with star, threaded one three different initial magnetic field topologies: (1) a pure dipole field, which also threads continuously everywhere; (2) excluded from surface currents; (3) threading superposed uniform axial field. A number exploratory are performed varying strength, density radius, magnitude stellar rotation rate. These designed as study magnetohydrodynamics region. Generally, we find that rapid occurs because angular momentum transport either Balbus-Hawley instability or braking effects. Equatorial results on dynamical timescale unless pressure exceeds ram accreting plasma; latter highly quantity. In case magnetospheric however, can result geometry inhibits polar even when pressures balance. contrast, occur regardless rate strong global fields combine create favorable net topology. Highly winds evident all topologies. generally channeled along lines have been opened through reconnection. speed variability outflows dependent strength Net torque star during measured positive, i.e., being spun up.