Unravelling cosmic velocity flows: a Helmholtz-Hodge decomposition algorithm for cosmological simulations
arXiv:2102.06217 · doi:10.1016/j.cpc.2021.107892
Abstract
In the context of intra-cluster medium turbulence, it is essential to be able to split the turbulent velocity field in a compressive and a solenoidal component. We describe and implement a new method for this aim, i.e., performing a Helmholtz-Hodge decomposition, in multi-grid, multi-resolution descriptions, focusing on (but not being restricted to) the outputs of AMR cosmological simulations. The method is based on solving elliptic equations for a scalar and a vector potential, from which the compressive and the solenoidal velocity fields, respectively, are derived through differentiation. These equations are addressed using a combination of Fourier (for the base grid) and iterative (for the refinement grids) methods. We present several idealised tests for our implementation, reporting typical median errors in the order of $1\unicode{x2030}$-, and with 95-percentile errors below a few percents. Additionally, we also apply the code to the outcomes of a cosmological simulation, achieving similar accuracy at all resolutions, even in the case of highly non-linear velocity fields. We finally take a closer look to the decomposition of the velocity field around a massive galaxy cluster.
12 pages, 8 figures; accepted for publication in Computer Physics Communications
References in corpus (12)
- Turbulent Heating in Galaxy Clusters Brightest in X-rays
- The Fractal Density Structure in Supersonic Isothermal Turbulence: Solenoidal versus Compressive Energy Injection
- Comparing Numerical Methods for Isothermal Magnetized Supersonic Turbulence
- On the amplification of magnetic fields in cosmic filaments and galaxy clusters
- Turbulence and Vorticity in Galaxy Clusters Generated by Structure Formation
- Turbulence and Particle Acceleration in Giant Radio Haloes: the Origin of Seed Electrons
- Simulation techniques for cosmological simulations
- The Matryoshka Run (II): Time Dependent Turbulence Statistics, Stochastic Particle Acceleration and Microphysics Impact in a Massive Galaxy Cluster
- Second order Fermi reacceleration mechanisms and large scale synchrotron radio emission in intra-cluster bridges
- Cosmological shock waves
- Large-Scale Structure Formation: from the first non-linear objects to massive galaxy clusters
- The Spanish Square Kilometre Array White Book