Simulations of Magnetorotational Turbulence with a Higher-Order Godunov Scheme

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(abridged) We apply a second-order Godunov code, Athena, to studies of the magnetorotational instability using unstratified shearing box simulations with a uniform net vertical field and a sinusoidally varying zero net vertical field.

• The Athena results agree well with similar studies that used different numerical algorithms.
• We conduct analyses to study the flow of energy from differential rotation to turbulent fluctuations to thermalization.
• A study of the temporal correlation between the time derivatives of volume-averaged energy components shows that energy injected into turbulent fluctuations dissipates on a timescale of $\Omega^{-1}$, where $\Omega$ is the orbital frequency of the local domain.