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In non-collisional magnetised astrophysical plasmas, vortices can form as it is the case of the Venus plasma wake where Lundin et al. (2013) identified a large vortex through the integration of data of many orbits from the Venus E...
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In non-collisional magnetised astrophysical plasmas, vortices can form as it is the case of the Venus plasma wake where Lundin et al. (2013) identified a large vortex through the integration of data of many orbits from the Venus Express (VEX) spacecraft. On the one hand, our purpose is to develop a theoretical foundation in order to explain the occurrence and formation of vortices in non-collisional astrophysical plasmas. On the other hand, to apply the latter in order to study the vorticity in the wakes of Venus and Mars. We introduce two theorems and two corollaries, which may be applicable to any non-collisional plasma system, that relate the vorticity to electromagnetic variables such as the magnetic field and the electric current density. We also introduce a toy vortex model for the wakes of non-magnetised planetary bodies. From the proposed theorems and model, and using magnetic data of the VEX and the Mars Global Surveyor (MGS) spacecraft, we identify vortices in the wakes of Venus and Mars in single spacecraft wake crossings. We also identify a spatial coincidence between current density and vorticity maxima confirming the consistency of our theorems and model. We conclude that vortices in non-collisional magnetised plasmas are always linked to electric currents and that both vortices and currents always coexist. This suggests that the mechanism that produces this type of vortices is the mutual interaction between the electric current and the magnetic field, that to a first approximation is explained considering that electric currents can be generated by the difference in the speeds of the plasma species, i. e., (u→)_p ≠ (u→)_e, which induce magnetic fields that modify the existing field and also produce a helical field configuration that drives charged particles along helical trajectories.
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It is shown that a vorticity, constructed from the spin field of a quantum spinning plasma, combines with the classical generalized vorticity (representing the magnetic and the velocity fields) to yield a new grand generalized vor...
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It is shown that a vorticity, constructed from the spin field of a quantum spinning plasma, combines with the classical generalized vorticity (representing the magnetic and the velocity fields) to yield a new grand generalized vorticity that obeys the standard vortex dynamics. Expressions for the quantum or spin vorticity and for the resulting generalized helicity invariant are derived. Reduction of the rather complex spinning quantum system to a well known and highly investigated classical form opens familiar channels for the delineation of physics peculiar to dense plasmas spanning solid state to astrophysical objects. A simple example is worked out to show that the magnetics of a spinning plasma can be much richer than that of the corresponding classical system.
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Systematic examinations are carried out experimentally about the contribution of background vorticity distributions (BGVD's) to the spontaneous formation and decay of ordered arrays (vortex crystals) composed of strong vortices (c...
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Systematic examinations are carried out experimentally about the contribution of background vorticity distributions (BGVD's) to the spontaneous formation and decay of ordered arrays (vortex crystals) composed of strong vortices (clumps) by using a pure-electron plasma. It is found that the BGVD level needs to be higher for an increasing number of clumps to form vortex crystals and that the number of the clumps constituting the crystal decreases in time as ∝ γ lnt in contrast to ∝ t~ξ with ξ ≈ 1 as accepted well in turbulence models. The decay rate y increases with the BGVD level. The observed configurations of the clumps cover the theoretically predicted catalogue of vortex arrays in superfluid helium, suggesting a possible relaxation path of the crystal states.
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We discuss the role of magnetic degrees of freedom in Yang—Mills plasma at temperaturesabove and of order of the critical temperature T0. While at zero temperature the magnetic degrees offreedom are condensed and electric degrees...
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We discuss the role of magnetic degrees of freedom in Yang—Mills plasma at temperaturesabove and of order of the critical temperature T0. While at zero temperature the magnetic degrees offreedom are condensed and electric degrees of freedom are confined, at the point of the phase transitionboth magnetic and electric degrees of freedom are released into the thermal vacuum. This phenomenonmight explain the observed unusual properties of the plasma.
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It is shown that the nonlinear dynamics of one-dimensional Shukla mode [Phys. Lett. A 316, 238 (2003)] is governed by a modified Kortweg-de Vries-Burgers equation. The latter admits stationary solutions in the form of either a sol...
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It is shown that the nonlinear dynamics of one-dimensional Shukla mode [Phys. Lett. A 316, 238 (2003)] is governed by a modified Kortweg-de Vries-Burgers equation. The latter admits stationary solutions in the form of either a solitary wave or a monotonic/oscillatory shock. The present nonlinear waves may help to understand the salient features of localized density and magnetic field structures in molecular dusty clouds as well as in low-temperature laboratory dusty plasma discharges. (C) 2003 American Institute of Physics. [References: 14]
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We derive the equation governing the asymptotic stationary states generated by decaying turbulence in two-dimensional plasma and planetary atmosphere. These fluids may be described by the Charney-Hasegawa-Mima equation and their r...
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We derive the equation governing the asymptotic stationary states generated by decaying turbulence in two-dimensional plasma and planetary atmosphere. These fluids may be described by the Charney-Hasegawa-Mima equation and their relaxation states show a high degree of organization in vortical flows, similar to the Euler fluid. We develop a field-theoretical framework and show that these systems attain at stationarity the extremum of an energy functional corresponding to self-dual fields.
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In the paper, the interaction between a finite-size vortex of constant density and a weak, pointlike vortex in a Penning trap is studied analytically. A suitable Fourier representation for the contour of the finite vortex is consi...
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In the paper, the interaction between a finite-size vortex of constant density and a weak, pointlike vortex in a Penning trap is studied analytically. A suitable Fourier representation for the contour of the finite vortex is considered and a model for small perturbations, which is linear with respect to the Fourier coefficients, is deduced. The resonance condition for the surface modes and a sufficient condition for the merger of the vortices not to occur are obtained. The validity of the analytic results is checked with a contour dynamics code making use of a new methodology developed by the authors. Numerical results referred to a case of strongly-interacting vortices are also reported.
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Experiments and theory characterize a novel type of spatial Landau damping, caused by a flux of particles through the wave or rotation resonance (critical) layer. Pure electron plasma experiments demonstrate that a steady flux of ...
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Experiments and theory characterize a novel type of spatial Landau damping, caused by a flux of particles through the wave or rotation resonance (critical) layer. Pure electron plasma experiments demonstrate that a steady flux of particles causes algebraic damping of diocotron mode amplitudes for azimuthal modes m = 1 and m = 2, and a simple model of dynamics in the nonlinear cat's eye clarifies the observations. This flux-driven algebraic damping is related to, but distinct from, the exponential decay characteristic of Landau damping. This flux-driven damping applies also to Kelvin waves on 2D vortices, and so may be broadly relevant to plasmas and geophysical flows.
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The problem of three-dimensional combined magnetic and velocity shear driven instabilities of a compressible magnetized jet modeled as a plane neutral/current double vortex sheet in the framework of the resistive magnetohydrodynam...
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The problem of three-dimensional combined magnetic and velocity shear driven instabilities of a compressible magnetized jet modeled as a plane neutral/current double vortex sheet in the framework of the resistive magnetohydrodynamics is addressed. The resulting dynamics given by the stream+current sheet interaction is analyzed and the effects of a variable geometry of the basic fields are considered. Depending on the basic asymptotic magnetic field configuration, a selection rule of the linear instability modes can be obtained. Hence, the system follows a two-stage path developing either through a fully three-dimensional dynamics with a rapid evolution of kink modes leading to a final turbulent state, or rather through a driving two-dimensional instability pattern that develops on parallel planes on which a reconnection+coalescence process takes place.
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To describe the nonlinear propagation of electrostatic drift waves the generalized Hasegawa-Mima equation containing both vector (Jacobian) and scalar (Korteweg-de Vries-type) nonlinearities is obtained for electron-positron-ion p...
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To describe the nonlinear propagation of electrostatic drift waves the generalized Hasegawa-Mima equation containing both vector (Jacobian) and scalar (Korteweg-de Vries-type) nonlinearities is obtained for electron-positron-ion plasmas. The drift waves are supposed to have arbitrary wavelengths (as compared with the Larmour radius of plasma ions at the plasma electron temperature). Temperature inhomogeneity of electrons and positrons is taken into account. Spatial increase in the linear plasma-potential perturbations in the direction of density and temperature inhomogeneities is shown. Self-organization mechanism of large-scale drift solitary vortices is considered. It is shown that the existence of positrons in plasma enriches the class of solutions of the generalized Hasegawa-Mima equation.
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