Turbulence and coherent structures in non-neutral plasmas

Romé, M.; Lepreti, F.

doi:10.1140/epjp/i2011-11038-4

Cited by 15 publications

(26 citation statements)

References 135 publications

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“…Although this situation is oversimplified and does not reproduce the most typical experimental conditions (discussed in the next Section), it already highlights the clear influence of dust contamination on the dynamics of the electron plasma. The results show that for the pure electron plasma the diocotron (Kelvin-Helmholtz) instability is fully developed over the span of the simulation and we can see the formation of five vortices (as seen both in the theory and experiments [8,7]). When dust is added we can clearly observe the presence of a higher number of active diocotron modes, with the formation of six vortices, but at the same time we can notice a slower overall dynamics (vortices are not fully developed yet), which means that the insurgence of the Kelvin-Helmholtz instability is effectively slowed down by the presence of the dust core.…”

Section: Numerical Investigationsmentioning

confidence: 63%

“…Specifically, the aim is the observation of the modifications in the plasma dynamics due to the presence of a dust population, with a focus on the effects of dust on stability, fluid turbulence and equilibrium properties of the electron component. The study comprises both a theoretical/numerical analysis and the design and realization of a Penning-Malmberg trap for tailored experiments, and represents a continuation and extension of the studies on pure electron plasmas previously performed within our research group [8].…”

Section: Introductionmentioning

confidence: 99%

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Experimental and numerical investigation of non-neutral complex plasmas

Romé

Cavaliere

Cavenago

et al. 2013

AIP Conference Proceedings

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Articles you may be interested inA Hamiltonian fluid-kinetic model for a two-species non-neutral plasma Phys. Plasmas 21, 044504 (2014); 10.1063/1.4871491 Production and study of high-beta plasma confined by a superconducting dipole magneta) Phys. Plasmas 13, 056111 (2006); 10.1063/1.2186616Simulations of the instability of the m=1 self-shielding diocotron mode in finite-length non-neutral plasmas Stability of highly asymmetric non-neutral plasmas Abstract. A plasma of particles with the same sign of charge, can be easily confined under ultrahigh vacuum conditions in Penning-Malmberg traps, where the time evolution of the system is monitored for very long times by means of electrostatic and optical diagnostic systems. Complex (dusty) plasmas are ionized gases that contain a distribution of micrometer-sized particles with a surface charge of the order of a few thousand electron charges. The interplay between a wide range of scales in time and space gives rise to new characteristic physical phenomena. Laboratory complex plasmas generally satisfy a global (quasi-)neutrality condition. A different concept is represented by a non-neutral complex plasma. To investigate the dynamics of this system, we are currently developing the DuEl (Dust-Electron) device, where negatively charged dust particles will be present together with a population of electrons. The experimental set-up will include a dust injection system and a Penning-Malmberg trap for the confinement of the dust-contaminated electron plasma. We describe here the main physical aims of the project and the present design of the apparatus. To support the experimental project, we have been developing a specifically tailored two-dimensional 'hybrid' Particle-In-Cell code. Using polar cylindrical coordinates, the code aims to investigate the transverse dynamics of a magnetized electron plasma contaminated by a massive, charged species. A mass-less fluid approximation for the electron population is exploited, while the dust component is treated with a kinetic description, also including the gravitational force. The preliminary results of systematic studies on the effects of heavy (magnetized or non-magnetized) dust grains on the equilibrium and stability properties of the electron fluid are presented. The implementation of other characteristic phenomena of interest, e.g. residual gas friction and dust charge fluctuations, is also under development.

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Section: Numerical Investigationsmentioning

confidence: 63%

Section: Introductionmentioning

confidence: 99%

Experimental and numerical investigation of non-neutral complex plasmas

Romé

Cavaliere

Cavenago

et al. 2013

AIP Conference Proceedings

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“…The equations form a noncanonical Hamiltonian system [19], characterized by the existence of two independent families of Casimir invariants, given by C 1 = dAF (n e ) and C 2 = dAd 2 vG ( f d ), with F and G arbitrary functions. The invariants include, as particular cases, the familiar invariants of the 2D Euler incompressible equations [20,9], such as the enstrophy, and those of the Vlasov equation, such as the entropy. In particular, the Hamiltonian structure of the model can be used to derive a set of stability conditions for rotating coherent structures of the two-species system.…”

Section: Physical Modelmentioning

confidence: 99%

“…The project shows aspects of significant novelty in the field of complex plasmas, with a combination of plasma magnetization, nonneutrality and dust contamination. A particular goal is the analysis of the effects of dust on the instabilities and the evolution of the turbulence of the electron component [9]. The analysis is restricted so far to the transverse dynamics of the system.…”

Section: Introductionmentioning

confidence: 99%

Effects of dust contamination on the transverse dynamics of a magnetized electron plasma

Romé¹,

Cavaliere²,

Cavenago³

et al. 2015

AIP Conference Proceedings

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Abstract. Complex (dusty) plasmas are characterized by the presence of a fraction of micrometric or sub-micrometric particles which may collect a surface charge up to the order of a few thousand electron charges. The dusty plasmas studied in the experiments generally satisfy a global neutrality condition. By contrast, we present here the investigation of a magnetized nonneutral plasma, i.e., a plasma with a single sign of charge (e.g. electrons) confined in a Penning-Malmberg trap, contaminated by a dust population. We simulate the two-dimensional transverse dynamics of this multi-component plasma with a particle-in-cell code implementing a mass-less fluid (drift-Poisson) approximation for the electrons and a kinetic description for the dust component (including gravity). Simulations with different initial dust distributions and densities have been performed in order to investigate the influence of the dust on the development of the diocotron instability in the electron plasma. In particular, the early stage of the growth of the diocotron modes has been analyzed by Fourier decomposition.

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“…A further simplification that can be adopted for these systems consists of considering a 2D dynamics. For pure electron plasmas in Penning-Malmberg traps the high-frequency longitudinal electron motion can be averaged out for a wide range of operational regimes, and the electron plasma dynamics becomes isomorphic to that of a 2D incompressible inviscid fluid, where the fluid vorticity corresponds to the electron density and the fluid stream function to the electrostatic potential [6,7]. A 2D multi-fluid model turns out to be appropriate also for a cold non-relativistic electronion system at high magnetic field strengths [1], while a kinetic treatment for the dynamics of the ion population is required at moderate values of the confining field.…”

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confidence: 99%

A Hamiltonian fluid-kinetic model for a two-species non-neutral plasma

2014

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A model for describing the dynamics of a pure electron plasma in the presence of a population of massive charged particles is presented. The model couples the fluid dynamics of the pure electron plasma with the dynamics of the massive particle population, the latter being treated kinetically. The model is shown to possess a noncanonical Hamiltonian structure and to preserve invariants analogous to those of the two-dimensional (2D) Euler equation for an incompressible inviscid fluid, and of the Vlasov equation. The Hamiltonian structure of the model is used to derive a set of stability conditions for rotating coherent structures of the two-species system, in the case of negatively charged massive particles. According to these conditions, stability is attained if both the equilibrium distribution function of the kinetic species and the equilibrium density of the electron fluid are monotonically decreasing functions of the corresponding single-particle energies in the rotating frame. For radially confined equilibria near the axis, the stability condition corresponds to the existence of a finite interval of rotation frequencies for the reference frame, with the upper bound determined by the presence of the kinetic population.

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Turbulence and coherent structures in non-neutral plasmas

Cited by 15 publications

References 135 publications

Experimental and numerical investigation of non-neutral complex plasmas

Experimental and numerical investigation of non-neutral complex plasmas

Effects of dust contamination on the transverse dynamics of a magnetized electron plasma

A Hamiltonian fluid-kinetic model for a two-species non-neutral plasma

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