Diocotron instability in non-neutral plasmas with a stationary point in the rotation frequency profile

Kotelnikov, I. A.; Pozzoli, R.; Romé, M.

doi:10.1063/1.2040177

Cited by 5 publications

(1 citation statement)

References 26 publications

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“…The level of vacuum inside the device is such that ionisation processes between the confined charges and the background neutrals can be neglected. To ensure that the equilibrium state exists over very long time-scales 5 , many dedicated theoretical and experimental studies have been carried out to avoid disruptive instabilities such as the azimuthal diocotron instability [6][7][8][9][10][11][12][13][14][15][16] and, to a lesser extent, axial resonant space-charge effects 1 . The confining electric potential along the magnetic field lines, which is imposed externally, is generally of the order of tens of V since the plasma temperature is of the order of a few eV 17 .…”

Section: Introductionmentioning

confidence: 99%

Self-consistent formation and steady-state characterisation of trapped high energy electron clouds in the presence of a neutral gas background

Bars¹,

Hogge²,

Loizu³

et al. 2022

Preprint

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This study considers the self-consistent formation and dynamics of electron clouds interacting with a background neutral gas through elastic and inelastic (ionisation) collisions in coaxial geometries similar to gyrotron electron guns. These clouds remain axially trapped as the result of crossed magnetic field lines and electric equipotential lines creating potential wells similar to those used in Penning traps. Contrary to standard Penning traps, in this study we consider a strong externally applied radial electric field which is of the same order as that of the space-charge field. In particular, the combination of coaxial geometry, strong radial electric fields and electron collisions with the residual neutral gas (RNG) present in the chamber induce non-negligible radial particle transport and ionisation. In this paper, the dynamics of the cloud density and currents resulting from electron-neutral collisions are studied using a 2D3V particle-in-cell code. Simulation results and parametric scans are hereby presented. Finally, a fluid model is derived to explain and predict the cloud peak density and peak radial current depending on the externally applied electric and magnetic fields, and on the RNG pressure.

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Section: Introductionmentioning

confidence: 99%

Self-consistent formation and steady-state characterisation of trapped high energy electron clouds in the presence of a neutral gas background

Bars¹,

Hogge²,

Loizu³

et al. 2022

Preprint

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Non-modal analysis of the diocotron instability: Cylindrical geometry

et al. 2013

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The temporal evolution of the linear diocotron instability of the cylindrical annular plasma column is investigated by employing the extension of the shearing modes methodology to the cylindrical geometry. It was obtained that the spatial time-dependent distortion of the electron density initial perturbations by shear flows leads to the non-modal evolution of the potential, which was referred to as the manifestation of the continuous spectrum. The evolution process leads toward the convergence to the phase-locking configuration of the mutually growing normal modes.

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Nonlinear shearing modes approach to the diocotron instability of a planar electron strip

Mikhailenko

et al. 2015

Physics of Plasmas

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The nonlinear evolution of the diocotron instability of a planar electron strip is investigated analytically by means of the nonlinear shearing mode for the solution of the initial and boundary value problems. The method is based on the sheared spatial coordinates which account for the motion of electron flow in the electrostatic field of the unstable diocotron modes in addition to the unperturbed sheared motion of the electron flow on the transformed shear coordinates. The time evolutions are studied by the solution of the initial and boundary value problems. The obtained solutions for the perturbed electrostatic potential include two nonlinear effects—the effect of the distortion of the boundaries of the planar electron strip and the effect of the coupling of the sheared nonmodal diocotron modes. It was proved by a two-dimensional particle-in-cell simulation that the developed theory is valid as long as the distortion of the boundaries of the basic shear flow does not change the frequency and growth rate of the linear diocotron instability in the transformed coordinates.

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Diocotron instability in non-neutral plasmas with a stationary point in the rotation frequency profile

Cited by 5 publications

References 26 publications

Self-consistent formation and steady-state characterisation of trapped high energy electron clouds in the presence of a neutral gas background

Self-consistent formation and steady-state characterisation of trapped high energy electron clouds in the presence of a neutral gas background

Non-modal analysis of the diocotron instability: Cylindrical geometry

Nonlinear shearing modes approach to the diocotron instability of a planar electron strip

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