Initial Configuration
We consider binary black hole mass ratios of $q=1$, $2$, and $4$. Each of these binaries are set on quasicircular orbits with angular velocities of $\Omega M= 0.0174, 0.0189,$ and $0.0204$, respectively. Here $M$ is the ADM mass of the system. We set the magnitude of the individual dimensionless black hole spins to $\chi = 0.26$, either lying in the initial orbital plane ($q=1$ case) or $45^{\circ}$ above it ($q=2, 4$ cases). The spacetime metric is built following the puncture formalism.
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The initial accretion disk satisfies the profile of a stationary disk around a single nonrotating black hole with the same mass as the ADM mass of the binary system. The disk adopts the equation of state $P=(\Gamma-1)\epsilon\rho_0$, where $P$ is the pressure, $\epsilon$ is the internal specific energy, $\Gamma$ is the adiabatic index, and $\rho_0$ is the rest mass density. We set $\Gamma=4/3$, which is appropriate for radiation pressure-dominated, optically thick disks.
We set the inner disk radius to $R_{in}=18M$ and the angular momentum to $l(R_{in})=5.25M$. The resulting disk has a peak pressure at ~ 30M. The accretion disk is seeded with a purely poloidal magnetic field confined to its interior, with a magnetic-to-gas pressure ratio of $P_{mag}/P_{gas}\approx 0.01$.
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