Modeling the Large‐Scale Structures of Astrophysical Jets in the Magnetically Dominated Limit

Li, Hui; Lapenta, Giovanni; Finn, John M.; Li, Shengtai; Colgate, Stirling A.

doi:10.1086/501499

Cited by 100 publications

(150 citation statements)

References 22 publications

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“…The magnitude of ∼ 10 18 ampères for the electric current associated with a 10 8 M BH, was originally predicted by Lovelace (1976). It is integral to the simulations of Li et al (2006) in Figure 3, and now tentatively confirmed in an actual measurement in (by Kronberg in Ji et al, 2008) as discussed above. Another success of this class of model is that the current-driven instabilities are more able than hydrodynamic, e.g.…”

Section: Poynting Flux Jetssupporting

confidence: 71%

“…Indeed RM ≈ 0 within measurement errors after subtracting the smoothed RM of nearby background at https://www.cambridge.org/core/terms. https://doi.org/10.1017/S1743921309031172 502 P. P. Kronberg The helical structure of a simulated "magnetic tower" poynting flux jet, after Li et al (2006). Right: Simulated current structure of a combined magnetic tower poynting flux jet + lobe system (Nakamura et al, 2008). sources.…”

Section: First Assumption-free Measurement Of An Extragalactic Jet Cumentioning

confidence: 99%

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Magnetic field transport from AGN cores to jets, lobes, and the IGM

Kronberg¹

2008

Proc. IAU

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Abstract. I describe various stages of energy flow along an extragalactic jet, which subsequently evolves into an extended lobe which is visible in radio and X-rays. The sizes of the lobes vary from kpc scales to several megaparsec, so that the largest lobes are clearly injecting back hole energy into the IGM on scales comparable with a galaxy-galaxy separation. This is sometimes loosely referred to as Black hole-IGM "feedback". My talk begins with a well-formed jet, and avoids the complex and unclarified physics at less than a few Schwarzschild radii that cause the initial launching the jet.This presentation focuses on recent thinking and supercomputer simulations that appear to clarify the fundamental nature of these remarkable jets and lobes. The energy transport process appears to be electrodynamic, rather than particle beam−driven. A new observational verification of a 10 18 Ampère current in an actual jet is concordant with the predictions and simulations of poynting flux-dominated electromagnetic jets. In this model the current is tightly related to the BH mass and angular energy.The magneto-plasma properties of the lobes must obviously match to the jets which feed them. The "energy sink" phase is when BH energy is ultimately deposited on supra-galactic scales. The process from the BH to the lobe production happens with remarkable efficiency. The presence or absence of a galaxy cluster environment creates laboratory conditions that help to calibrate the energy flow paths, and the magnetic rigidity of these jet-lobe systems.I conclude by describing recent, sensitive radio observations on supra-cluster scales that test for final magnetic energy deposition -the "sink" phase -into the intergalactic medium.

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Section: Poynting Flux Jetssupporting

confidence: 71%

Section: First Assumption-free Measurement Of An Extragalactic Jet Cumentioning

confidence: 99%

Magnetic field transport from AGN cores to jets, lobes, and the IGM

Kronberg¹

2008

Proc. IAU

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“…Recent observations [2] have demonstrated that the MHD kink instability occurs in solar flux ropes which can disrupt yielding twisted magnetic clouds [3] that thread the solar system. The kink instability is important for MHD models of astrophysical jets [4,5] and is often invoked to explain the observation of kinked structures in their synchrotron emission [6]. MHD kink modes are also observed in laboratory Z-pinch [7] and tokamak plasmas, and during spheromak formation are thought to mediate the conversion of toroidal to poloidal magnetic flux [8,9].…”

Section: Introductionmentioning

confidence: 99%

Effects of boundary conditions and flow on the kink instability in a cylindrical plasma column

et al. 2007

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An experimental investigation of the kink instability is presented in a linear plasma column where one end is line-tied to the plasma source, and the other end is not line-tied and therefore free to slide over the surface of the end-plate. This latter boundary condition is a result of plasma sheath resistance that insulates, at least partially, the plasma from the end-plate. The helical m = 1 kink mode is observed to grow when the plasma current exceeds a threshold and, close to the criticality, is characterized by an axial mode structure with maximum displacement at the free axial boundary. Azimuthal rotation of the mode is observed such that the helically kinked column always screws into the free axial boundary. The kink mode structure, rotation frequency and instability threshold are accurately reproduced by a recent kink theory [D. D. Ryutov, et al., Phys. Plasmas 13, 032105 (2006)], which includes axial plasma flow and one end of the plasma column that is free to move due to a perfect non-line-tying boundary condition which is experimentally verified. A brief review of the kink theory and its predictions for the boundary conditions relevant in the present experiments are presented.

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“…This code has been used to simulate AGN jets in the intracluster medium (Li et al 2006) and the Caltech plasma jet experiment (Zhai et al 2014). The spatial domain is a mesh cube with 96 grid points in each Cartesian dimension and nonreflecting outflow boundary conditions.…”

Section: Ideal Mhd Simulationmentioning

confidence: 99%

Apex Dips of Experimental Flux Ropes: Helix or Cusp?

Wongwaitayakornkul

Haw

et al. 2017

ApJ

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We present a new theory for the presence of apex dips in certain experimental flux ropes. Previously such dips were thought to be projections of a helical loop axis generated by the kink instability. However, new evidence from experiments and simulations suggest that the feature is a 2D cusp rather than a 3D helix. The proposed mechanism for cusp formation is a density pileup region generated by nonlinear interaction of neutral gas cones emitted from fast-gas nozzles. The results indicate that density perturbations can result in large distortions of an erupting flux rope, even in the absence of significant pressure or gravitational forces. The density pileup at the apex also suppresses the m=1 kink mode by acting as a stationary node. Consequently, more accurate density profiles should be considered when attempting to model the stability and shape of solar and astrophysical flux ropes.

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Modeling the Large‐Scale Structures of Astrophysical Jets in the Magnetically Dominated Limit

Cited by 100 publications

References 22 publications

Magnetic field transport from AGN cores to jets, lobes, and the IGM

Magnetic field transport from AGN cores to jets, lobes, and the IGM

Effects of boundary conditions and flow on the kink instability in a cylindrical plasma column

Apex Dips of Experimental Flux Ropes: Helix or Cusp?

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