# Density and B-field Evolution

## Mass Ratio = 4:1

We follow the evolution of the matter and magnetic fields of a gaseous disk. In the cavity of the disk are two black holes, with a mass ratio of q = 1:4. Green lines depict magnetic field lines within the disk. The seeding points used in drawing these fields lines were taken from a subset of fluid test-particles that were evolved during the simulation. By drawing magnetic field lines from these test-particles, we can visualize the evolution of the magnetic field lines, because they are attached ("frozen in") to the same particles for all time. White lines highlight the field lines threading the polar regions above the black holes. These field lines are drawn from fixed grid points above each black hole pole.

Here, we focus on the post-decoupling phase, during which $t_{vis} \gt t_{GW}$ and the binary decouples from the disk before the disk can relax. As q decreases the 'lump' on the cavity wall diminishes. The rate of gas accretion is larger for the more massive companion.

 Fig. 1-1 Fig. 1-2 Fig. 1-3
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