Session GP1 - Poster Session IV.
POSTER session, Tuesday afternoon, October 30
Exhibit Hall B,
Magnetorotational Instability (MRI) is a powerful candidate mechanism for the fast transport of angular momentum in magnetized accretion disks. In an accretion disk, when the mass spirals in towards the stellar object, due to gravity, the velocity increases to conserve angular momentum. When the force of gravity is balanced with the centripetal force, the viscosity pulls it in towards the central compact object, which is too small to explain the fast transport of mass, so there must be another reason. Hydrodynamic (HD) instabilities, like the Rayleigh instability, are ineffective in producing turbulence in accretion disks because it requires a negative gradient of specific angular momentum. Magnetohydrodynamics provides a better description of plasma in hot accretion flows where angular momentum has an extra degree of freedom due to the presence of the magnetic field. The radial transport of angular momentum due to MRI will hopefully explain how mass gets accreted onto a stellar object. Despite the popularity of MRI, it has never been tested in the laboratory. In an attempt to demonstrate MRI in the laboratory, a magnetized couette flow experiment using gallium is proposed. Before gallium is used, a prototype experiment using water has been constructed to study linear and nonlinear HD instability in the (omega1, omega2) space. HD stability can be monitored using particle imaging velocimeter techniques, which will serve as a reference for effects due to the MRI mechanism.