Star formation in galaxies appears to be self-regulated by energetic feedback processes. Among the most promising agents of are cosmic rays (CRs), relativistic ion population interstellar and intergalactic plasmas. In these environments, CRs virtually collisionless interact via collective phenomena mediated kinetic-scale plasma waves large-scale magnetic fields. The enormous separation kinetic global astrophysical scales requires a hydrodynamic description. Here, we develop new macroscopic...

ABSTRACT Feedback mediated by cosmic rays (CRs) is an important process in galaxy formation. Because CRs are long-lived and because they transported along the magnetic field lines independently of any gas flow, can efficiently distribute their feedback energy within galaxy. We present in-depth investigation (i) how launch galactic winds from a disc that forming $10^{11} \, \rm {M}_\odot$ halo (ii) state CR transport inside wind. To this end, we use arepo moving-mesh code model with...

Abstract Cosmic-ray (CR) feedback is critical for galaxy formation as CRs drive galactic winds, regularize star in galaxies, and escape from active nuclei to heat the cooling cores of clusters. The strength depends on their coupling background plasma and, such, effective CR transport speed. Traditionally, this has been hypothesized depend balance between wave growth CR-driven instabilities damping. Here, we study physics first principles, starting a gyrotropic distribution ions that stream...

Abstract Transport equations for electron thermal energy in the high- β e intracluster medium (ICM) are developed that include scattering from both classical collisions and self-generated whistler waves. The calculation employs an expansion of kinetic equation along ambient magnetic field limit strong assumes waves with low phase speeds V w ∼ v te / ≪ dominate turbulent spectrum, speed ≫ 1 ratio to pressure. We find: (1) temperature-gradient-driven whistlers when L c > , mean free path...

The particle-in-cell (PIC) method is successfully used to study magnetized plasmas. However, this requires large computational costs and limits simulations short physical run times often set-ups of less than three spatial dimensions. Traditionally, circumvented either via hybrid-PIC methods (adopting massless electrons) or magneto-hydrodynamic-PIC (modelling the background plasma as a single charge-neutral magneto-hydrodynamical fluid). Because both preclude modelling important...

The circumgalactic medium (CGM) plays a critical role in galaxy evolution, influencing gas flows, feedback processes, and galactic dynamics. Observations show substantial cold reservoir the CGM, but mechanisms driving its formation evolution remain unclear. Cosmic rays (CRs), as source of non-thermal pressure, are increasingly recognized key regulators This study explores how CRs affect clouds that condense from hot CGM via thermal instability (TI). Using 3D CR-magnetohydrodynamic (CRMHD)...

Abstract Cosmic-ray-driven (CR-driven) instabilities play a decisive role during particle acceleration at shocks and CR propagation in galaxies galaxy clusters. These amplify magnetic fields modulate transport so that the intrinsically collisionless population is tightly coupled to thermal plasma provides dynamical feedback. Here, we show CRs with finite pitch angle drive electromagnetic waves (along background field) unstable on intermediate scales between gyroradii of ions electrons as...

Thermal electrons cannot directly participate in the process of diffusive acceleration at electron-ion shocks because their Larmor radii are smaller than shock transition width: this is well-known electron injection problem acceleration. Instead, an efficient pre-acceleration must exist that scatters off electromagnetic fluctuations on scales much shorter ion gyro radius. The recently found intermediate-scale instability provides a natural way to produce such parallel shocks. drives comoving...

We present a new numerical algorithm to solve the recently derived equations of two-moment cosmic ray hydrodynamics (CRHD). The is implemented as module in moving mesh Arepo code. Therein, anisotropic transport rays (CRs) along magnetic field lines discretised using path-conservative finite volume method on unstructured time-dependent Voronoi Arepo. interaction CRs and gyroresonant Alfvén waves described by short-timescale source terms CRHD equations. employ custom-made semi-implicit...

We study the underlying physics of cosmic ray (CR)-driven instabilities that play a crucial role for CR transport across wide range scales, from interstellar to galaxy cluster environments. By examining linear dispersion relation CR-driven in magnetised electron–ion background plasma, we establish both intermediate and gyroscale have resonant origin, show these resonances can be understood via simple graphical interpretation. These destabilise wave modes parallel large-scale magnetic field...

Feedback mediated by cosmic rays (CRs) is an important process in galaxy formation. Because CRs are long-lived and because they transported along magnetic field lines independently of any gas flow, can efficiently distribute their feedback energy within the galaxy. We present in-depth investigation (i) how launch galactic winds from a disc that forming $10^{11} \mathrm{M}_\odot$ halo (ii) CR transport affects dynamics outflow. To this end, we use Arepo moving-mesh code model with two-moment...

Winds from hot massive stars are driven by scattering of continuum radiation in bound–bound transitions. This radiative driving is subject to a strong instability, leading shocks and X-ray emission. Time-dependent simulations the instability encounter problems both for absorption lines, it necessary introduce an artificially low opacity cut-off κm. The non-linear growth inner steeply accelerating wind is, so far, badly resolved. We present with time-dependent Euler Lagrange codes pure line...

Recent observations with the MeerKAT radio telescope reveal a unique population of faint non-thermal filaments pervading central molecular zone (CMZ). Some those are organized into groups almost parallel filaments, seemingly sorted by their length, so that morphology resembles harp emitting "strings". We argue synchrotron GeV electrons these harps have been consecutively injected same source (a massive star or pulsar) spatially intermittent magnetic fiber bundles within flux tube via...

Cosmic ray (CR) hydrodynamics is a (re-)emerging field of high interest due to the importance CRs for dynamical evolution interstellar, circumgalactic, and intracluster medium. In these environments, with GeV energies can influence large-scale dynamics by regulating star formation, driving galactic winds or altering pressure balance halos. Recent efforts have moved focus community from one-moment description CR transport towards two-moment model as this allows more accurate microphysics...

Photospheric radiation can drive winds from hot, massive stars by direct momentum transfer through scattering in bound–bound transitions of atmospheric ions. The line force should cause a new radiative wave mode. dispersion relation perturbations the was analysed so far either Sobolev approximation or for pure absorption. former does not include line-driven instability, and latter cannot account upstream propagating, waves. We consider non-Sobolev that includes simplified way, accounting...

Transport equations for electron thermal energy in the high $\beta_e$ intracluster medium (ICM) are developed that include scattering from both classical collisions and self-generated whistler waves. The calculation employs an expansion of kinetic equation along ambient magnetic field limit strong assumes waves with low phase speeds $V_w\sim{v}_{te}/\beta_e\ll{v}_{te}$ dominate turbulent spectrum, $v_{te}$ speed $\beta_e\gg1$ ratio to pressure. We find: (1) temperature-gradient-driven...

Cosmic ray (CR) feedback is critical for galaxy formation as CRs drive galactic winds, regularize star in galaxies, and escape from active nuclei to heat the cooling cores of clusters. The strength depends on their coupling background plasma and, such, effective CR transport speed. Traditionally, this has been hypothesized depend balance between wave growth CR-driven instabilities damping. Here, we study physics first principles, starting a gyrotropic distribution ions that stream along...

Feedback processes in galaxies dictate their structure and evolution. Baryons can be cycled through stars, which inject energy into the interstellar medium (ISM) supernova explosions, fueling multiphase galactic winds. Cosmic rays (CRs) accelerated at remnants are an important component of feedback. CRs effectively contribute to wind driving; however, impact heavily depends on assumed CR transport model. We run high-resolution "tallbox" simulations a patch disk using moving mesh...

Abstract The formation of galaxies is significantly influenced by galactic winds, possibly driven cosmic rays due to their long cooling times and better coupling plasma compared radiation. In this study, we compare the radio observations edge-on galaxy NGC 4217 from CHANG-ES collaboration catalog with a mock observation an isolated based on arepo simulation that adopts state-of-the-art two-moment ray transport treatment multiphase interstellar medium model. We find significant agreement...

Galactic outflows influence the evolution of galaxies not only by expelling gas from their disks but also injecting energy into circumgalactic medium (CGM). This alters or even prevents inflow fresh onto disk and thus reduces star formation rate. Supernovae (SNe) are engines galactic winds as they release thermal kinetic interstellar (ISM). Cosmic rays (CRs) accelerated at shocks SN remnants constitute a small fraction overall budget. However, long live-times allow them to act far away...

The formation of galaxies is significantly influenced by galactic winds, possibly driven cosmic rays due to their long cooling times and better coupling plasma compared radiation. In this study, we compare the radio observations edge-on galaxy NGC 4217 from CHANG-ES collaboration catalog with a mock observation an isolated based on arepo simulation that adopts state-of-the-art two-moment ray transport treatment multiphase interstellar medium model. We find significant agreement between...

The particle-in-cell (PIC) method is successfully used to study magnetized plasmas. However, this requires large computational costs and limits simulations short physical run-times often setups in less than three spatial dimensions. Traditionally, circumvented either via hybrid-PIC methods (adopting massless electrons) or magneto-hydrodynamic-PIC (modelling the background plasma as a single charge-neutral magneto-hydrodynamical fluid). Because both preclude modelling important plasma-kinetic...

We study the underlying physics of cosmic-ray (CR) driven instabilities that play a crucial role for CR transport across wide range scales, from interstellar to galaxy cluster environments. By examining linear dispersion relation CR-driven in magnetised electron-ion background plasma, we establish both, intermediate and gyroscale have resonant origin show these resonances can be understood via simple graphical interpretation. These destabilise wave modes parallel large-scale magnetic field...

Cosmic rays (CRs) play an important role in many astrophysical systems. Acting on plasma scales to galactic environments, CRs are usually modeled as a fluid, using the CR energy density evolving quantity. This method comes with flaw that corresponding evolution equation is not conservative form it contains adiabatic source term couples thermal gas. In absence of non-adiabatic changes, instead entropy physically equivalent option avoids this potential numerical inconsistency. work, we study...