On the mechanism of self gravitating Rossby interfacial waves in proto-stellar accretion discs

Yellin-Bergovoy, Ron; Heifetz, Eyal; Umurhan, O. M.

doi:10.1080/03091929.2016.1158816

Cited by 10 publications

(9 citation statements)

References 36 publications

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“…Therefore, we expect that the evolution of the RWI vortices formed in our calculations almost never changes even in the 3D frameworks. The effect of self-gravity prevents the onset of the RWI (Lovelace & Hohlfeld 2013;Yellin-Bergovoy et al 2016). However, once the RWI vortex is formed, there are possibilities that self-gravity can help the vortex survive for a long time .…”

Section: Other Physical Effectsmentioning

confidence: 99%

Parametric Study of the Rossby Wave Instability in a Two-dimensional Barotropic Disk. II. Nonlinear Calculations

Ono

Muto

Tomida

et al. 2018

ApJ

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Vortices in protoplanetary disks have attracted attention since the discovery of lopsided structures. One of the possible mechanisms for producing vortices is the Rossby Wave Instability (RWI). In our previous work, we have performed detailed linear stability analyses of the RWI with various initial conditions. In this paper, we perform numerical simulations of the vortex formation by the RWI in 2D barotropic disks using the Athena++ code. As initial conditions, we consider axisymmetric disks with a Gaussian surface density bump of various contrasts and half-widths. Perturbations grow as expected from the linear stability analyses in the linear and weakly non-linear regimes. After the saturation, multiple vortices are formed in accordance with the most unstable azimuthal mode and coalesce one after another. In the end, only one quasi-stationary vortex (the RWI vortex) remains, which migrates inward. During the RWI evolution, the axisymmetric component approaches the stable configuration. We find that the axisymmetric component reaches the marginally stable state for the most unstable azimuthal mode at the saturation and the marginally stable state for the m = 1 mode at the final vortex merger. We investigate the structure and evolution of the RWI vortices. We obtain some empirical relations between the properties of the RWI vortices and the initial conditions. Using tracer particle analyses, we find that the RWI vortex can be considered as a physical entity like a large fluid particle. Our results provide a solid theoretical ground for quantitative interpretation of the observed lopsided structures in protoplanetary disks.

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Section: Other Physical Effectsmentioning

confidence: 99%

Parametric Study of the Rossby Wave Instability in a Two-dimensional Barotropic Disk. II. Nonlinear Calculations

Ono

Muto

Tomida

et al. 2018

ApJ

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“…citet-ZhuBaruteau2016 have shown that disc self-gravity weakens the vortex development at artificial density bumps. Lovelace & Hohlfeld (2013) and recently Yellin-Bergovoy, Heifetz, & Umurhan (2016), however, have shown that the disc self-gravity should be included in the RWI simulations for discs with the Toomre parameter Q < Qcrit = (1/h), where h is the geometric aspect ratio (here G = 1 code unit is applied, see details in the next section). For a flatdisc-surface geometry with h = 0.05 this corresponds to Qcrit = 20.…”

Section: Introductionmentioning

confidence: 99%

Vortex stretching in self-gravitating protoplanetary discs

Regály

Vorobyov

2017

Monthly Notices of the Royal Astronomical Society

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Horseshoe-shaped brightness asymmetries of several transitional discs are thought to be caused by large-scale vortices. Anticyclonic vortices are efficiently collect dust particles, therefore they can play a major role in planet formation. Former studies suggest that the disc self-gravity weakens vortices formed at the edge of the gap opened by a massive planet in discs whose masses are in the range of 0.01 M disc /M * 0.1.Here we present an investigation on the long-term evolution of the large-scale vortices formed at the viscosity transition of the discs' dead zone outer edge by means of two-dimensional hydrodynamic simulations taking disc self-gravity into account. We perform a numerical study of low mass, 0.001 M disc /M * 0.01, discs, for which cases disc self-gravity was previously neglected. The large-scale vortices are found to be stretched due to disc self-gravity even for low-mass discs with M disc /M * 0.005 where initially the Toomre Q-parameter was 50 at the vortex distance. As a result of stretching, the vortex aspect ratio increases and a weaker azimuthal density contrast develops. The strength of the vortex stretching is proportional to the disc mass. The vortex stretching can be explained by a combined action of a non-vanishing gravitational torque caused by the vortex, and the Keplerian shear of the disc. Selfgravitating vortices are subject to significantly faster decay than non-self-gravitating ones. We found that vortices developed at sharp viscosity transitions of self-gravitating discs can be described by a GNG model as long as the disc viscosity is low, i.e. α dz 10 −5 .

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“…A very similar form of the above equation, which included self-gravity term as well, was obtained in the cylindrical coordinate system for proto-stellar accretion disks by Yellin-Bergovoy, Heifetz, and Umurhan 28 . In the absence of gravity, the above equation will produce a "vorticity-density wave" (which becomes a pure vorticity wave when ρ 1 = ρ 2 ): (2.21) shows that shear too, along with gravity, is affected by the variations in density.…”

Section: 21)mentioning

confidence: 74%

“…Umurhan 28 (they have obtained the cylindrical coordinate version, which is more relevant for accretion disks). We intend to understand the generation mechanism of shear-density waves, which is not yet properly understood.…”

Section: 21)mentioning

confidence: 99%

On the inertial effects of density variation in stratified shear flows

Guha

Raj

2018

Physics of Fluids

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In this paper, we first revisit the celebrated Boussinesq approximation in stratified flows. Using scaling arguments we show that when the background shear is weak, the Boussinesq approximation yields either (i)is the ratio of density variation to the mean density and F r c is the ratio of the phase speed to the long wave speed. The second clause implies, contrary to the commonly accepted notion, that a flow with large density variations can also be Boussinesq.Indeed, we show that deep water surface gravity waves are Boussinesq while shallow water surface gravity waves arent. However, in the presence of moderate/strong shear, Boussinesq approximation implies the conventionally accepted A t O(1). To understand the inertial effects of density variation, our second objective is to explore various non-Boussinesq shear flows and study different kinds of stably propagating waves that can be present at an interface between two fluids of different background densities and vorticities. Furthermore, three kinds of density interfaces -neutral, stable and unstable -embedded in a background shear layer, are investigated. Instabilities ensuing from these configurations, which includes Kelvin-Helmholtz, Holmboe, Rayleigh-Taylor and triangular-jet, are studied in terms of resonant wave interactions. The effects of density stratification and the shear on the stability of each of these flow configurations are explored. Some of the results, e.g. the destabilizing role of density stratification, stabilizing role of shear, etc. are apparently counter-intuitive, but physical explanations are possible if the instabilities are interpreted from wave interactions perspective.

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On the mechanism of self gravitating Rossby interfacial waves in proto-stellar accretion discs

Cited by 10 publications

References 36 publications

Parametric Study of the Rossby Wave Instability in a Two-dimensional Barotropic Disk. II. Nonlinear Calculations

Parametric Study of the Rossby Wave Instability in a Two-dimensional Barotropic Disk. II. Nonlinear Calculations

Vortex stretching in self-gravitating protoplanetary discs

On the inertial effects of density variation in stratified shear flows

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