We present a hydrodynamical simulation of the turbulent, magnetized, supernova (SN)-driven interstellar medium (ISM) in stratified box that dynamically couples injection and evolution cosmic rays (CRs) self-consistent chemical composition. CRs are treated as relativistic fluid advection-diffusion approximation. The thermodynamic gas is computed using network follows abundances H+, H, H2, CO, C+, free electrons includes (self-)shielding dust. find perceptibly thicken disk with heights 90%...

We present simulations of the magnetized interstellar medium (ISM) in models massive star forming (40 Msun / yr) disk galaxies with high gas surface densities (~100 pc^2) similar to observed high-redshift disks. assume that type II supernovae deposit 10 per cent their energy into ISM as cosmic rays and neglect additional deposition thermal or momentum. With a typical Galactic diffusion coefficient for CRs (3e28 cm^2 s) we demonstrate this process alone can trigger local formation strong low...

We investigate the impact of cosmic rays (CRs) on galactic outflows from a multi-phase interstellar medium with solar neighbourhood conditions. The three-dimensional magneto-hydrodynamical simulations include CRs as relativistic fluid in advection-diffusion approximation. thermal and chemical state ISM is computed non-equilibrium network. find that (injected 10 \% supernova energy) efficiently support launching strongly affect their phase structure. Outflows leaving midplane are denser...

We report the first results of global galactic-scale cosmic ray (CR)–MHD simulations CR-driven dynamo. investigate dynamics magnetized interstellar medium (ISM), which is dynamically coupled with CR gas. assume that exploding stars deposit small-scale, randomly oriented, dipolar magnetic fields into differentially rotating ISM, together a portion CRs, accelerated in supernova shocks. conduct numerical aid new parallel MHD code PIERNIK. find initial magnetization galactic disks by forms...

The stable propagation of jets in FRII sources is remarkable if one takes into account that large-scale are subjected to potentially highly disruptive three-dimensional (3D) Kelvin-Helmholtz instabilities. Numerical simulations can address this problem and help clarify the causes stability. Following previous studies stability relativistic flows two dimensions (2D), it our aim test extend conclusions such works three dimensions. We present numerical for study properties 3D, sheared, flows....

We present the first numerical model of magnetohydrodynamic cosmic-ray-driven dynamo type proposed by Parker in 1992. The driving force amplification process comes from cosmic rays injected into Galactic disk randomly distributed spherical regions representing supernova remnants. underlying is differentially rotating. An explicit resistivity responsible for dissipation small-scale magnetic field component. obtain large-scale on a timescale 250 Myr.

<i>Aims. <i/>We present a parameter study of the magnetohydrodynamical-dynamo driven by cosmic rays in interstellar medium (ISM), focusing on efficiency magnetic-field amplification and issue energy equipartition between magnetic, kinetic, cosmic-ray (CR) energies.<i>Methods. perform numerical CR-MHD simulations ISM using an extended version ZEUS-3D code shearing-box approximation taking into account presence Ohmic resistivity, tidal forces, vertical disk gravity. CRs are supplied...

Cosmic ray (CR) protons are an important component in many astrophysical systems. Processes like CR injection, cooling, adiabatic changes as well active transport through the medium strongly modify momentum distribution and have to be taken into account hydrodynamical simulations. We present efficient novel numerical scheme accurately compute evolution of particle function by solving Fokker-Planck equation with a low number spectral bins (10 - 20), which is required include full spectrum for...

We study the possible magnetization of cosmic voids by void galaxies. Recently, observations revealed isolated starforming galaxies within voids. Furthermore, a major fraction volume is expected to be filled with magnetic fields minimum strength about $10^{-15}$ G on Mpc scales. estimate transport energy rays (CR) from into assume that CRs and winds are able leave small shortly after they assembled, then propagate For typical void, we field filling factor depending its galaxy population...

The linear and non-linear stability of sheared, relativistic planar jets is studied by means analysis numerical hydrodynamical simulations. Our results extend the previous Kelvin-Hemlholtz studies for relativistic, in vortex sheet approximation performed Perucho et al. (2004a, A&A, 427, 415; 2004b, 431) including a shear layer between jet external medium more general perturbations. models considered span wide range Lorentz factors () internal energies are classified into three classes...

We present three-dimensional global numerical simulations of the cosmic-ray (CR) driven dynamo in barred galaxies. study evolution interstellar medium galaxy presence non-axisymmetric component potential, i.e., bar. The magnetohydrodynamical is by CRs, which are continuously supplied to disk supernova (SN) remnants. No magnetic field at beginning but one-tenth SN explosions a source small-scale randomly oriented dipolar field. In all models we assume that 10% 10^51 erg kinetic energy output...

We present a numerical algorithm for the incorporation of active cosmic ray transport into ZEUS-3D magnetohydrodynamical code. The is described by diffusion-advection equation. applied form diffusion tensor allows anisotropic rays along and across magnetic field direction, which controlled two parameters: parallel perpendicular coefficients. implemented tested comparison diffusive to analytical solutions Our method numerically stable wide range coefficients, including realistic values...

We discuss the Parker instability of Galactic interstellar medium, focusing on cosmic-ray gas injection by supernova remnants and its propagation, through diffusion equation. describe in thin flux-tube approximation solve equations numerically. find that triggered cosmic rays is faster than excited "small vertical perturbation" there no lower limit for horizontal scale raised magnetic loops. a very strong dynamo effect transport disk across large-scale field.

The effects of relativistic dynamics and thermodynamics in the development Kelvin-Helmholtz instabilities planar, jets along early phases (namely linear saturation phases) evolution has been studied by a combination stability analysis high-resolution numerical simulations for most unstable first reflection modes temporal approach. Three different values jet Lorentz factor (5, 10 20) few specific internal energy matter (from 0.08 to ) have considered. Figures illustrating perturbations are...

We investigate streaming instability using two-fluid approximation (neutral gas and dust) in a quasi-global, unstratified protoplanetary disc, with the help of piernik code. compare amplification rate eigenmode numerical simulations, corresponding growth resulting from linear stability analysis full system Euler's equation including aerodynamic drag. Following Youdin & Goodman (2005), we show that (1) rapid dust clumping occurs due to difference azimuthal velocities dust, coupled by drag...

Certain aspects of the (linear and nonlinear) stability sheared relativistic (slab) jets are analyzed. The linear problem has been solved for a wide range jet models well inside ultrarelativistic domain (flow Lorentz factors up to 20, specific internal energies approximately 60c2). As distinct feature our work, we have combined analytical approach with high-resolution hydrodynamical simulations, which allowed us (i) identify, in regime, resonant modes shear layer, (ii) confirm result...

We investigate the influence of Coriolis force and magnetic reconnection on evolution Parker instability in galactic disks. apply a model local gas cube, permeated by an azimuthal large-scale field solve numerically resistive 3D MHD equations including contribution force. introduce current-dependent resistivity which switches above certain critical current density. study topology formation poloidal fields from initial field. Our simulations demonstrate that leads to helically twisted flux...

In this paper we continue our study of the Kelvin-Helmholtz (KH) instability in relativistic planar jets following long-term evolution numerical simulations which were introduced Paper I. The models have been classified into four classes (I to IV) with regard their nonlinear phase, characterized by process jet/ambient mixing and momentum transfer. Models undergoing qualitatively different non-linear are clearly grouped well-separated regions a jet Lorentz factor/jet-to-ambient enthalpy...

<i>Context. <i/>Irregular galaxies are usually smaller and less massive than their spiral, S0, elliptical counterparts. Radio observations indicate that a magnetic field is present in irregular whose value similar to spiral galaxies. However, the conditions interstellar medium of an galaxy unfavorable for amplification because slow rotation low shearing rate.<i>Aims. <i/>We investigate cosmic-ray driven dynamo galaxy. We study its efficiency under weak shear. The star formation also taken...

Star-forming dwarf galaxies can be seen as the local proxies of high-redshift building blocks more massive according to current paradigm hierarchical galaxy formation. They are low-mass objects, and therefore their rotation speed is very low. Several observed show quite strong magnetic fields. These cases ordered fields seem correlate with a high, but not extremely star formation rate. We investigate whether these could generated by cosmic-ray-driven dynamo. The environment unfavourable for...

We report a three-dimensional (3D) numerical model of the Parker instability with cosmic rays and shear in galactic disk compute components dynamo coefficients α β from electromotive forces obtained simulations. For first time we apply well-known statistical procedures to fit modeled terms tensors. compare our results kinematic other methods coefficient estimation. Although do not solve all problems physical interpretation tensors find that presented give us ability them desired quality. The...