The Magnetohydrodynamics of Supersonic Gas Clouds: MHD Cosmic Bullets and Wind‐swept Clumps

Jones, T. W.; Ryu, Dongsu; Tregillis, I. L.

doi:10.1086/178151

Cited by 95 publications

(171 citation statements)

References 33 publications

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“…This will then determine the class of the given cloud distribution, Ã I or Ã M . For cloud distributions from the set Ã I with average cloud separation hDy N i > d crit , evolution of the clouds during the compression, re-expansion, and destruction phases will proceed in the noninteracting regime, and the formalism for a single-cloud interaction with a shock wave (e.g., Klein et al 1994;Jones et al 1996;Mac Low et al 1994;Lim & Raga 1999) can be used to describe the system. On the other hand, if the cloud separation is less than the critical distance, the clouds in the layer will merge into a single structure before their destruction is completed.…”

Section: Discussionmentioning

confidence: 99%

Hydrodynamic Interaction of Strong Shocks with Inhomogeneous Media. I. Adiabatic Case

Poludnenko¹,

Frank²,

Blackman³

2002

ApJ

118

143

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Many astrophysical flows occur in inhomogeneous (clumpy) media. We present results of a numerical study of steady, planar shocks interacting with a system of embedded cylindrical clouds. Our study uses a two-dimensional geometry. Our numerical code uses an adaptive mesh refinement, allowing us to achieve sufficiently high resolution both at the largest and the smallest scales. We neglect any radiative losses, heat conduction, and gravitational forces. Detailed analysis of the simulations shows that interaction of embedded inhomogeneities with the shock/postshock wind depends primarily on the thickness of the cloud layer and arrangement of the clouds in the layer. The total cloud mass and the total number of individual clouds is not a significant factor. We define two classes of cloud distributions: thin and thick layers. We define the critical cloud separation along the direction of the flow and perpendicular to it, distinguishing between the interacting and noninteracting regimes of cloud evolution. Finally, we discuss mass loading and mixing in such systems.

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Section: Discussionmentioning

confidence: 99%

Hydrodynamic Interaction of Strong Shocks with Inhomogeneous Media. I. Adiabatic Case

Poludnenko¹,

Frank²,

Blackman³

2002

ApJ

118

143

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“…035 of the determination of the jet ridge in this image reported by Blundell & Bowler, (2004). For the settings of the jet dynamics we chose the following characteristic values: a geometry factor η = 1; a ratio l sh /l cl = 0.5 of the thickness of the radio bright shells around the jet clouds to the size of the clouds, the finding of Inoue et al, (2012) for supernova remnants; a pressure ratio of the thermal gas and magnetic field β g = 1, which is expected in the vicinity of the jet clouds, where the magnetic field is amplified by the shocks (Jones et al, 1996;Inoue et al, 2012); a ratio of the energy densities of the magnetic field and relativistic particles β H = 3/4, which corresponds minimum total energy of the field and particles (Ginzburg, 1979, p. 95); an initial flux of kinetic energy in the jet per cloud fraction, L k ≡Ṁ j v 2 j /2 = 10 39 erg/s, and a temperature of the jet clouds T cl = 2 × 10 4 K at a distance of 10 15 cm, which are very tightly determined for the optical jet . The jet mass-fluxṀ j was assumed to be constant throughout the jet length.…”

Section: Simulation Of the Dynamical Jets Of Ss 433mentioning

confidence: 99%

Simulation of kinematics of SS 433 radio jets that interact with the ambient medium

Panferov

2014

A&A

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Context. The mildly relativistic jets of SS 433 are believed to inflate the surrounding supernova remnant W 50, possibly depositing more than 99% of their kinetic energy in the remnant expansion. Where and how this transformation of the energy occurs is as yet unknown. We can learn from this that the jets decelerate and that this deceleration is non-dissipative. Aims. We uncover the deviation of the arcsecond-scale precessing radio jets of SS 433 from the ballistic locus described by the kinematic model as a signature of the dynamics issuing from the interaction of the jets with the ambient medium. Methods. To do this, we simulated the kinematics of these jets, taking into account the ram pressure on the jets, which we estimated from the profile of brightness of synchrotron radiation along the radio jets, assuming pressure balance in the jets. Results. We found that to fit an observable locus in all scales the radio jets need to be decelerated and twisted in addition to the precession torsion, mostly within the first one-fifth of the precession period, and subsequently they extend in a way that imitates ballistic jets. This jet kinematics implies a smaller distance to SS 433 than the currently accepted 5.5 kpc. The physical parameters of the jet model, which links jets dynamics with radiation, are physically reliable and characteristic for the SS 433 jets. The model proposes that beyond the radio-brightening zone, the jet clouds expand because they are in pressure balance with the intercloud medium, and heat up with distance according to the law T = 2 × 10 4 (r/10 15 cm) 1.5 K. Conclusions. This model naturally explains and agrees with, the observed properties of the radio jets: a) the shock-pressed morphology; b) the brightness profile; c) the ∼10% deflections of the jet kinematics from the standard kinematic model -a magnitude of the jet speed decrement in our simulation; d) the precession-phase deviations from the standard kinematic model predictions; e) the dichotomy of the distances to the object, 4.8 kpc vs. 5.5 kpc, which are determined on the basis of the jet kinematics on scales of sub-arcsecond and several arcseconds, respectively; and f) the reheating on arcsecond scales.

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“…Electric fields produced by jet-stretched magnetic field lines around an obstacle would also accelerate particles (e.g. Jones et al 1996).…”

Section: Introductionmentioning

confidence: 99%

Coupling hydrodynamics and radiation calculations for star-jet interactions in active galactic nuclei

Cita

Bosch‐Ramon

Paredes-Fortuny

et al. 2016

A&A

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Context. Stars and their winds can contribute to the non-thermal emission in extragalactic jets. Because of the complexity of jet-star interactions, the properties of the resulting emission are closely linked to those of the emitting flows. Aims. We simulate the interaction between a stellar wind and a relativistic extragalactic jet and use the hydrodynamic results to compute the non-thermal emission under different conditions. Methods. We performed relativistic axisymmetric hydrodynamical simulations of a relativistic jet interacting with a supersonic, non-relativistic stellar wind. We computed the corresponding streamlines out of the simulation results and calculated the injection, evolution, and emission of non-thermal particles accelerated in the jet shock, focusing on electrons or e ± -pairs. Several cases were explored, considering different jet-star interaction locations, magnetic fields, and observer lines of sight. The jet luminosity and star properties were fixed, but the results are easily scalable when these parameters are changed. Results. Individual jet-star interactions produce synchrotron and inverse Compton emission that peaks from X-rays to MeV energies (depending on the magnetic field), and at ∼100-1000 GeV (depending on the stellar type), respectively. The radiation spectrum is hard in the scenarios explored here as a result of non-radiative cooling dominance, as low-energy electrons are efficiently advected even under relatively high magnetic fields. Interactions of jets with cold stars lead to an even harder inverse Compton spectrum because of the Klein-Nishina effect in the cross section. Doppler boosting has a strong effect on the observer luminosity. Conclusions. The emission levels for individual interactions found here are in the line of previous, more approximate, estimates, strengthening the hypothesis that collective jet-star interactions could significantly contribute at high energies under efficient particle acceleration.

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The Magnetohydrodynamics of Supersonic Gas Clouds: MHD Cosmic Bullets and Wind‐swept Clumps

Cited by 95 publications

References 33 publications

Hydrodynamic Interaction of Strong Shocks with Inhomogeneous Media. I. Adiabatic Case

Hydrodynamic Interaction of Strong Shocks with Inhomogeneous Media. I. Adiabatic Case

Simulation of kinematics of SS 433 radio jets that interact with the ambient medium

Coupling hydrodynamics and radiation calculations for star-jet interactions in active galactic nuclei

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