Linear stability of an impulsively accelerated density interface in an ideal two-fluid plasma

Li, Yuan; Bakhsh, Abeer; Samtaney, Ravi

doi:10.1063/5.0080404

Cited by 3 publications

(2 citation statements)

References 40 publications

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“…As such they are intended here as continuum systems assumed to be described at microscopic level by a phase-space statis-tics determined by a local (and possibly Maxwellian) kinetic distribution function (KDF). For ideal systems of this type the pressure P is a position-dependent scalar function expressed by the well-known ideal relationship (in IS dimensional units) P = nT [9].…”

Section: Introductionmentioning

confidence: 99%

“…Its precise form should in principle be determined separately based on phenomenological models and/or microscopic (i.e., kinetic) physics that pertains the structure and interactions occurring among the same constituents of the fluid, possibly subject to external fields [25][26][27]. A particular case that belongs to this category pertains to ideal fluids [28], to be intended as continuum systems described at microscopic level by a phase-space statistics determined by a local and possibly Maxwellian KDF. For ideal systems of this type the pressure P is a positiondependent scalar function expressed by the well-known ideal relationship (in IS dimensional units) P = nT .…”

Section: Introductionmentioning

confidence: 99%

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Polytropic representation of the kinetic pressure tensor of non-ideal magnetized fluids in equilibrium toroidal structures

et al. 2023

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Non-ideal fluids are generally subject to the occurrence of non-isotropic pressure tensors, whose determination is fundamental in order to characterize their dynamical and thermodynamical properties. This requires the implementation of theoretical frameworks provided by appropriate microscopic and statistical kinetic approaches in terms of which continuum fluid fields are obtained. In this paper, the case of non-relativistic magnetized fluids forming equilibrium toroidal structures in external gravitational fields is considered. Analytical solutions for the kinetic distribution function are explicitly constructed, to be represented by a Chapman–Enskog expansion around a Maxwellian equilibrium. In this way, different physical mechanisms responsible for the generation of non-isotropic pressures are identified and proved to be associated with the kinetic constraints imposed on single and collective particle dynamics by phase-space symmetries and magnetic field. As a major outcome, the validity of a polytropic representation for the kinetic pressure tensors corresponding to each source of anisotropy is established, whereby directional pressures exhibit a specific power-law functional dependence on fluid density. The astrophysical relevance of the solution for the understanding of fluid plasma properties in accretion-disk environments is discussed.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Polytropic representation of the kinetic pressure tensor of non-ideal magnetized fluids in equilibrium toroidal structures

et al. 2023

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Polytropic representation of non-isotropic kinetic pressure tensor for non-ideal plasma fluids in relativistic jets

Cremaschini

2023

Physics of Fluids

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Non-ideal fluids are likely to be affected by the occurrence of pressure anisotropy effects, whose understanding for relativistic systems requires knowledge of the energy–momentum tensor. In this paper, the case of magnetized jet plasmas at equilibrium is considered, in which both microscopic velocities of constituent particles and the continuum fluid flow are treated as relativistic ones. A theoretical framework based on covariant statistical kinetic approach is implemented, which permits the proper treatment of single-particle and phase-space kinetic constraints and, ultimately, the calculation of the system continuum fluid fields associated with physical observables. A Gaussian-like solution for the kinetic distribution function (KDF) is constructed, in which the physical mechanism responsible for the generation of temperature anisotropy is identified with magnetic moment conservation. A Chapman–Enskog representation of the same KDF is then obtained in terms of expansion around an equilibrium isotropic Juttner distribution. This permits the analytical calculation of the fluid 4-flow and stress–energy tensor and the consequent proof that the corresponding kinetic pressure tensor is non-isotropic. As a notable result, the validity of a polytropic representation for the perturbative non-isotropic pressure contributions is established, whereby directional pressures exhibit specific power-law functional dependences on fluid density.

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Plasma kinetics: Discrete Boltzmann modeling and Richtmyer–Meshkov instability

Song,

Xu,

Miao

et al. 2024

Physics of Fluids

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In this paper, a discrete Boltzmann method (DBM) for plasma kinetics is proposed and further used to investigate the non-equilibrium characteristics in Orszag–Tang (OT) vortex and Richtmyer–Meshkov instability (RMI) problems. The construction of DBM mainly considers two aspects. The first is to build a physical model with sufficient capability to capture underlying physics. The second is to devise schemes for extracting more valuable information from massive data. For the first aspect, the generated model is equivalent to a magnetohydrodynamic model, and a coarse-grained model for extracting the most relevant thermodynamic non-equilibrium (TNE) behaviors including the entropy production rate. For the second aspect, the DBM uses non-conserved kinetic moments of (f−feq) to describe the non-equilibrium states and behaviors of complex systems. It is found that (i) for OT vortex, the entropy production rate and compression difficulty first increase and then decrease with time. (ii) For RMI with interface inversion and re-shock process, the influence of magnetic field on TNE effects shows stages: before the interface inversion, the TNE strength is enhanced by delaying the interface inversion; while after the interface inversion, the TNE strength is significantly reduced. Both the global average TNE strength and entropy production rate contributed by non-organized energy flux can be used as physical criteria to identify whether or not the magnetic field is sufficient to prevent the interface inversion. In general, this paper proposes a generalized physical modeling and analysis scheme that has the potential for investigating the kinetic physics in plasma.

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Linear stability of an impulsively accelerated density interface in an ideal two-fluid plasma

Cited by 3 publications

References 40 publications

Polytropic representation of the kinetic pressure tensor of non-ideal magnetized fluids in equilibrium toroidal structures

Polytropic representation of the kinetic pressure tensor of non-ideal magnetized fluids in equilibrium toroidal structures

Polytropic representation of non-isotropic kinetic pressure tensor for non-ideal plasma fluids in relativistic jets

Plasma kinetics: Discrete Boltzmann modeling and Richtmyer–Meshkov instability

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