Magnetorotational instability with smoothed particle hydrodynamics

The magnetorotational instability (MRI) is an important process in driving turbulence sufficiently ionized accretion disks. It has been extensively studied using simulations with Eulerian grid codes, but remains fairly unexplored for meshless codes. Here, we present a thorough numerical study on the MRI smoothed particle magnetohydrodynamics method geometric density average force expression. We performed 37 shearing box different initial setups and wide range of resolution dissipation parameters. show, first time, that sustained can be simulated successfully smoothed-particle hydrodynamics (SPH), results consistent prior work grid-based including saturation properties such as magnetic kinetic energies their respective stresses. In particular, stratified boxes, our reproduce characteristic “butterfly” diagram dynamo saturated at least 100 orbits. On contrary, traditional SPH suffer from runaway growth develop unphysically large azimuthal fields, similar to recent methods. investigated dependency Prandtl number ( P m ) SPH, focusing unstratified, zero net-flux case. found only larger than ?2.5, critical values physical grid-code simulations. However, unlike increases resolution, fixed number, resulting energy stresses are independent resolution. Mean-field analyses were all simulations, transport coefficients indicate no ? -effect unstratified cases, active ?? diamagnetic pumping effect medium, which generally agreement previous studies. There clear indication shear-current simulation, likely responsible weaker mean-field tall, simulation.