Formation of quasistationary vortex and transient hole patterns through vortex merger

Ganesh, R.; Lee, J. K.

doi:10.1063/1.1513154

Cited by 9 publications

(23 citation statements)

References 23 publications

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“…The vorticity contour plot of this configuration is shown in Figure . From previous study , it is known that N pv should be chosen below a critical value ( N pv = 7) to have persistent vortex hole pattern. We also note

\frac{R_{pv}}{R_{pa}} = \sqrt{\frac{N_{italicpv}}{N_{pv} - 1}}

from earlier studies , and choose our parameters such that the generated frequencies do not get affected by choice of the ratio

\frac{R_{pv}}{R_{pa}}

and still the point‐like vortices can excite the Kelvin waves on the surface of the patch vortex.…”

Section: Resultsmentioning

confidence: 99%

“…Further, they form a “vortex crystal” along with some “holes” (region of zero vorticity) within the distorted patch vortex. For τ m = 0 and incompressible neutral fluid, it has been shown that these vortex crystals are quite long‐lived …”

Section: Resultsmentioning

confidence: 99%

“…From previous study [31,34,44,45] it is known that N pv should be chosen below a critical value (N pv = 7) to have persistent vortex hole pattern. We also note R R = √ N N −1 from earlier studies [34,44,45] and choose our parameters such that the generated frequencies do not get affected by choice of the ratio R R and still the point-like vortices can excite the Kelvin waves on the surface of the patch vortex. Using the above initial profiles, we proceed to simulate the vortex merger problem discussed above using AG-Spect code.…”

Section: Multiple Rotating Vorticesmentioning

confidence: 99%

“…We time evolve the above set of equations with the pre-arranged structure of vortices and observe the merging quite similar to what was observed earlier for a neutral fluid or a pure electron plasma. [34] Some snapshots of time evolution of such a pre-arranged vortex merger are given in Figure 9 for N pv = 5, M = 0.04, m = 10 −4 , and √ m = 0.447.…”

Section: 31mentioning

confidence: 99%

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Viscoelastic effects on asymmetric two‐dimensional vortex patterns in a strongly coupled dusty plasma

Gupta

Mukherjee

Ganesh

2019

Contributions to Plasma Physics

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Strongly coupled dusty plasma medium is often described as a viscoelastic fluid that retains its memory. In a flowing dusty plasma medium, vortices of different sizes appear when the flow does not remain laminar. The vortices also merge to transfer energy between different scales. In the present work, we study the effect of viscoelasticity and compressibility over a localized vortex structure and multiple rotational vortices in a strongly coupled viscoelastic dusty plasma medium. In case of single rotating vortex flow, a transverse wave is generated from the localized vortex source and the evolution time of generated waves is found to be reduced due to finite viscoelasticity and compressibility of the medium. It is found that the viscoelasticity suppresses the dispersion of vorticity. In the presence of multiple vortices, we find, the vortex mergers get highly affected in the presence of memory effect of the fluid, and thus the dynamics of the medium gets completely altered compared to a non‐viscoelastic fluid. For a compressible fluid, viscoelasticity dampens the energy in the sonic waves generated in the medium. Thus a highly viscoelastic and compressible fluid, in some cases, behaves similarly to an incompressible viscoelastic fluid. The wave‐front like rings propagate in elliptical orbits keeping the footprint of the earlier position of the point‐vortex. The rings collide with each other even within the patch vortex region forming regions of high vorticity at the point of intersection and pass through each other.

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\frac{R_{pv}}{R_{pa}} = \sqrt{\frac{N_{italicpv}}{N_{pv} - 1}}

from earlier studies , and choose our parameters such that the generated frequencies do not get affected by choice of the ratio

\frac{R_{pv}}{R_{pa}}

and still the point‐like vortices can excite the Kelvin waves on the surface of the patch vortex.…”

Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Section: Multiple Rotating Vorticesmentioning

confidence: 99%

Section: 31mentioning

confidence: 99%

See 2 more Smart Citations

Viscoelastic effects on asymmetric two‐dimensional vortex patterns in a strongly coupled dusty plasma

Gupta

Mukherjee

Ganesh

2019

Contributions to Plasma Physics

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“…A two-dimensional radial-azimuthal explicit and electrostatic particle-in-cell code [39] was utilized to investigate the instability development and spoke dynamics. The code was extensively benchmarked and validated [40,41,42] and the convergence was also verified with different time steps, cell sizes and particles per cell in our study. An equidistant computational grids 64 × 512 in the radial and azimuthal dimensions was used.…”

Section: Pic/mcc Model Descriptionmentioning

confidence: 91%

Direct evidence of the gradient drift instability being the origin of a rotating spoke in a crossed field plasma

Xu,

Eremin,

Brinkmann

2021

Preprint

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A plasma rotating spoke in a crossed field discharge is studied using 2D radial-azimuthal fully kinetic Particle-In-Cell Monte Carlo Collision (PIC/MCC) simulations. The kinetic model reveals the whole perturbation spectrum of the gradient drift instability in the linear stage: Simon-Hoh, lower-hybrid and ion sound modes, providing direct evidence of the spoke of the gradient drift instability nature. The two-fluid dispersion relation of the gradient drift instability was utilized to analyze the linear development of instabilities in the simulations. The charge separation effect was incorporated in the fluid linear theory and a super-resolution signal processing method (multiple signal classification) was applied to obtain the numerical frequency spectrum. The simulated spectrum and growth rate show excellent agreement with the theoretical dispersion relation (real frequency and imaginary frequency) over investigated cases. The most linearly unstable mode was found to be the lower hybrid instability and the mode transition into the m=1 macroscopic rotating structure after saturation of the linear phase is accompanied by an inverse energy cascade. In the nonlinear stage, the pronounced spoke phenomena can occur when the heating of E θ × B electron flow channeled in the spoke front passage suffices to provide the enhanced ionization.

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Molecular and hydrodynamic descriptions of shear flows in two-dimensional strongly coupled dusty plasmas

Gupta

2022

Rev. Mod. Plasma Phys.

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Formation of quasistationary vortex and transient hole patterns through vortex merger

Cited by 9 publications

References 23 publications

Viscoelastic effects on asymmetric two‐dimensional vortex patterns in a strongly coupled dusty plasma

Viscoelastic effects on asymmetric two‐dimensional vortex patterns in a strongly coupled dusty plasma

Direct evidence of the gradient drift instability being the origin of a rotating spoke in a crossed field plasma

Molecular and hydrodynamic descriptions of shear flows in two-dimensional strongly coupled dusty plasmas

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