cuHARM : a new GPU accelerated GR-MHD code and its application to ADAF disks

Abstract

We introduce a new GPU-accelerated general-relativistic magneto-hydrodynamic (GR-MHD) code based on HARM which we call cuHARM. The code is written in CUDA-C and uses OpenMP to parallelize multi-GPU setups. Our code allows us to run high resolution simulations of accretion disks and the formation and structure of jets without the need of multi-node supercomputer infrastructure. A $256^3$ simulation is well within the reach of an Nvidia DGX-V100 server, with the computation being a factor about 10 times faster if only the CPU was used. We use this code to examine several disk structures all in the SANE state. We find that: (i) increasing the magnetic field, while in the SANE state does not affect the mass accretion rate; (ii) Simultaneous increase of the disk size and the magnetic field, while keeping the ratio of energies fixed, lead to the destruction of the jet once the magnetic flux through the horizon decrease below a certain limit. This demonstrates that the existence of the jet is not a linear function of the initial magnetic field strength; (iii) the structure of the jet is a weak function of the adiabatic index of the gas, with relativistic gas tend to have a wider jet.

33 pages, 16 figures, submitted to ApJ

References in corpus (24)

• First M87 Event Horizon Telescope Results. I. The Shadow of the Supermassive Black Hole
• Athena: A New Code for Astrophysical MHD
• First M87 Event Horizon Telescope Results. VIII. Magnetic Field Structure near The Event Horizon
• Advection-Dominated Accretion and the Black Hole Event Horizon
• Global General Relativistic MHD Simulation of a Tilted Black-Hole Accretion Disk
• ECHO: an Eulerian Conservative High Order scheme for general relativistic magnetohydrodynamics and magnetodynamics
• The Influence of Magnetic Field Geometry on the Evolution of Black Hole Accretion Flows: Similar Disks, Drastically Different Jets
• Equation of State in Relativistic Magnetohydrodynamics: variable versus constant adiabatic index
• Semi-implicit scheme for treating radiation under M1 closure in general relativistic conservative fluid dynamics codes
• Three-Dimensional Simulations of Magnetized Thin Accretion Disks around Black Holes: Stress in the Plunging Region
• The Disc-Jet Symbiosis Emerges: Modeling the Emission of Sagittarius A* with Electron Thermodynamics
• Comparing Numerical Methods for Isothermal Magnetized Supersonic Turbulence
• Polarimetric properties of Event Horizon Telescope targets from ALMA
• Cholla : A New Massively-Parallel Hydrodynamics Code For Astrophysical Simulation
• How important is non-ideal physics in simulations of sub-Eddington accretion onto spinning black holes?
• The Accretion flow in M87 is really MAD
• The Jet-Disk Boundary Layer in Black Hole Accretion
• GRMHD Simulations and Modeling for Jet Formation and Acceleration Region in AGNs
• Scale-invariant radio jets and varying black hole spin
• grim: A Flexible, Conservative Scheme for Relativistic Fluid Theories
• Looking for the underlying cause of black hole X-ray variability in GRMHD simulations
• Radiation Hydrodynamics in Kerr Spacetime: Equations without Coordinate Singularity at the Event Horizon
• The content of astrophysical jets
• Machine Learning for Conservative-to-Primitive in Relativistic Hydrodynamics