Mach stem hysteresis: Experiments addressing a novel explanation of clumpy astrophysical jet emission

Yirak, Kristopher; Foster, J. M.; Hartigan, Patrick; Wilde, B. H.; Douglas, M. R.; Paguio, R. R.; Blue, B. E.; Martínez, Durruty Jesús de Alba; Farley, D. R.; Rosen, P. A.; Frank, Adam

doi:10.1016/j.hedp.2013.01.006

Cited by 5 publications

(6 citation statements)

References 19 publications

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“…Multiple-epoch HST images show evidence for time-variable enhanced emission at intersection points of bow shocks exists in HH 34S and possibly also HH 47A (Hartigan et al 2011). Laboratory experiments of this phenomena have quantified the critical angles where Mach stems can form (Foster et al 2010;Yirak et al 2013), and the experiments agree reasonably well with the theoretical and numerical predictions.…”

Section: Narrow [S Ii] Filaments In the South Pillars Regionsupporting

confidence: 52%

A Survey of Irradiated Pillars, Globules, and Jets in the Carina Nebula

Hartigan

Reiter

Smith

et al. 2015

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We present wide-field, deep narrowband H 2 , Brγ, Hα, [S II], [O III], and broadband I and K-band images of the Carina star formation region. The new images provide a large-scale overview of all the H 2 and Brγ emission present in over a square degree centered on this signature star forming complex. By comparing these images with archival HST and Spitzer images we observe how intense UV radiation from O and B stars affects star formation in molecular clouds. We use the images to locate new candidate outflows and identify the principal shock waves and irradiated interfaces within dozens of distinct areas of star-forming activity. Shocked molecular gas in jets traces the parts of the flow that are most shielded from the intense UV radiation. Combining the H 2 and optical images gives a more complete view of the jets, which are sometimes only visible in H 2 . The Carina region hosts several compact young clusters, and the gas within these clusters is affected by radiation from both the cluster stars and the massive stars nearby. The Carina Nebula is ideal for studying the physics of young H II regions and PDR's, as it contains multiple examples of walls and irradiated pillars at various stages of development. Some of the pillars have detached from their host molecular clouds to form proplyds. Fluorescent H 2 outlines the interfaces between the ionized and molecular gas, and after removing continuum, we detect spatial offsets between the Brγ and H 2 emission along the irradiated interfaces. These spatial offsets can be used to test current models of PDRs once synthetic maps of these lines become available.

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Section: Narrow [S Ii] Filaments In the South Pillars Regionsupporting

confidence: 52%

A Survey of Irradiated Pillars, Globules, and Jets in the Carina Nebula

Hartigan

Reiter

Smith

et al. 2015

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“…From the experimental data we measure the position and shape of the leading shock wave. We measure the radial position (r), defined as the distance from the axis of symmetry of the bow shock to its intersection with the cone directly from the radiographs (see Yirak et al 2013). Likewise, the length of the Mach stem is defined in the images as the distance from the location where the Mach stem intersects the surface of the cone to the triple point where the Mach stem, bow shock, and reflected shock meet.…”

Section: Experimental Designmentioning

confidence: 99%

“…In this paper we extend the laser experimental work of Foster et al (2010) to a platform where we control the intersection angle between a strong shock and a surface by constructing targets with shapes designed to (a) keep the intersection angle constant, (b) decrease the intersection angle suddenly to below the critical value, and then gradually increase it above that value and (c) compare shock propagation over smooth and rough surfaces. Initial results of the work were published by Yirak et al (2013). Here we compile all the data from two years of experiments at the Omega laser facility, and supplement the experimental data with a series of numerical simulations of intersecting shocks.…”

Section: Introductionmentioning

confidence: 99%

When Shock Waves Collide

Hartigan

Foster

Frank

et al. 2016

ApJ

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Supersonic outflows from objects as varied as stellar jets, massive stars and novae often exhibit multiple shock waves that overlap one another. When the intersection angle between two shock waves exceeds a critical value, the system reconfigures its geometry to create a normal shock known as a Mach stem where the shocks meet. Mach stems are important for interpreting emission-line images of shocked gas because a normal shock produces higher postshock temperatures and therefore a higher-excitation spectrum than an oblique one does. In this paper we summarize the results of a series of numerical simulations and laboratory experiments designed to quantify how Mach stems behave in supersonic plasmas that are the norm in astrophysical flows. The experiments test analytical predictions for critical angles where Mach stems should form, and quantify how Mach stems grow and decay as intersection angles between the incident shock and a surface change. While small Mach stems are destroyed by surface irregularities and subcritical angles, larger ones persist in these situations, and can regrow if the intersection angle changes to become more favorable. The experimental and numerical results show that although Mach stems occur only over a limited range of intersection angles and size scales, within these ranges they are relatively robust, and hence are a viable explanation for variable bright knots observed in HST images at the intersections of some bow shocks in stellar jets.

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“…In the event of an incident shock wave producing a reflected shock from a solid boundary, there exists a critical angle φ c between the incident shock and the solid boundary, above which a fluid parcel cannot pass through both the incident and the reflected shocks while maintaining its original trajectory [49]. Once the critical angle is exceeded, the solution of the flow evolves into a new configuration consisting of an additional third shock which is normal to the solid boundary.…”

Section: D Mach Reflectionmentioning

confidence: 99%

“…In the absence of a solid body, a Mach stem can be produced by the intersection of two co-moving bow shocks [49]. In such From the initial hot spots, detonation waves propagate outward towards each other, intersect and then continue propagating.…”

Section: D Mach Reflectionmentioning

confidence: 99%

Detonation modeling with the Particles on Demand method

Sawant¹,

Dorschner²,

Karlin³

2022

Preprint

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A kinetic model based on the Particles on Demand method is introduced for gas phase detonation hydrodynamics in conjunction with the Lee-Tarver reaction model. The proposed model is realized on two-and three-dimensional lattices and is validated with a set of benchmarks. Quantitative validation is performed with the Chapman-Jouguet theory up to a detonation wave speed of Mach 20 in one dimension. Two-dimensional outward expanding circular detonation is tested for isotropy of the model as well as for the asymptotic detonation wave speed. Mach reflection angles are verified in setups consisting of interacting strong bow shocks emanating from detonation. Spherical detonation is computed to show viability of the proposed model for three dimensional simulations.

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Mach stem hysteresis: Experiments addressing a novel explanation of clumpy astrophysical jet emission

Cited by 5 publications

References 19 publications

A Survey of Irradiated Pillars, Globules, and Jets in the Carina Nebula

A Survey of Irradiated Pillars, Globules, and Jets in the Carina Nebula

When Shock Waves Collide

Detonation modeling with the Particles on Demand method

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