Influence of plasma background on 3D scrape-off layer filaments

David Schworer; Nicholas Ross Walkden; Huw Leggate; Benjamin Daniel Dudson; F. Militello; T Downes; Miles Turner

doi:10.1088/1361-6587/aae8fe

Influence of plasma background on 3D scrape-off layer filaments

David Schworer, Nicholas Ross Walkden, Huw Leggate, Benjamin Daniel Dudson, F. Militello, T Downes, Miles Turner

Physics

Research output: Contribution to journal › Article › peer-review

Abstract

This paper presents the effect of self-consistent plasma backgrounds including plasma-neutral interactions, on the dynamics of filament propagation. The principle focus is on the influence of the neutrals on the filament through both direct interactions and through their influence on the plasma background. Both direct and indirect interactions influence the motion of filaments. A monotonic increase of filament peak velocity with upstream electron temperature is observed, while a decrease with increasing electron density is observed. If ordered by the target temperature, the density dependence disappears and the filament velocity
is only a function of the target temperature. Smaller filaments keep a density dependence, as a result of the density dependence of the plasma viscosity. The critical size δ∗, where filaments are fastest, is shifted to larger sizes for higher densities, due to the plasma viscosity. If the density dependence of the plasma viscosity is removed, δ∗ has no density dependence, but rather a temperature dependence.

Original language	English
Article number	025008
Number of pages	12
Journal	Plasma Physics and Controlled Fusion
Volume	61
Issue number	2
Early online date	17 Oct 2018
DOIs	https://doi.org/10.1088/1361-6587/aae8fe
Publication status	Published - 6 Dec 2018

Bibliographical note

© 2018 Culham Centre for Fusion Energy. This is an author-produced version of the published paper. Uploaded in accordance with the publisher’s self-archiving policy. Further copying may not be permitted; contact the publisher for details.

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10.1088/1361-6587/aae8fe

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© 2018 Culham Centre for Fusion Energy. This is an author-produced version of the published paper. Uploaded in accordance with the publisher’s self-archiving policy. Further copying may not be permitted; contact the publisher for details.
Accepted author manuscript, 1.34 MBLicence: CC BY-NC-ND

Cite this

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title = "Influence of plasma background on 3D scrape-off layer filaments",

abstract = "This paper presents the effect of self-consistent plasma backgrounds including plasma-neutral interactions, on the dynamics of filament propagation. The principle focus is on the influence of the neutrals on the filament through both direct interactions and through their influence on the plasma background. Both direct and indirect interactions influence the motion of filaments. A monotonic increase of filament peak velocity with upstream electron temperature is observed, while a decrease with increasing electron density is observed. If ordered by the target temperature, the density dependence disappears and the filament velocityis only a function of the target temperature. Smaller filaments keep a density dependence, as a result of the density dependence of the plasma viscosity. The critical size δ∗, where filaments are fastest, is shifted to larger sizes for higher densities, due to the plasma viscosity. If the density dependence of the plasma viscosity is removed, δ∗ has no density dependence, but rather a temperature dependence.",

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AU - Schworer, David

AU - Walkden, Nicholas Ross

AU - Leggate, Huw

AU - Dudson, Benjamin Daniel

AU - Militello, F.

AU - Downes, T

AU - Turner, Miles

N1 - © 2018 Culham Centre for Fusion Energy. This is an author-produced version of the published paper. Uploaded in accordance with the publisher’s self-archiving policy. Further copying may not be permitted; contact the publisher for details.

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N2 - This paper presents the effect of self-consistent plasma backgrounds including plasma-neutral interactions, on the dynamics of filament propagation. The principle focus is on the influence of the neutrals on the filament through both direct interactions and through their influence on the plasma background. Both direct and indirect interactions influence the motion of filaments. A monotonic increase of filament peak velocity with upstream electron temperature is observed, while a decrease with increasing electron density is observed. If ordered by the target temperature, the density dependence disappears and the filament velocityis only a function of the target temperature. Smaller filaments keep a density dependence, as a result of the density dependence of the plasma viscosity. The critical size δ∗, where filaments are fastest, is shifted to larger sizes for higher densities, due to the plasma viscosity. If the density dependence of the plasma viscosity is removed, δ∗ has no density dependence, but rather a temperature dependence.

AB - This paper presents the effect of self-consistent plasma backgrounds including plasma-neutral interactions, on the dynamics of filament propagation. The principle focus is on the influence of the neutrals on the filament through both direct interactions and through their influence on the plasma background. Both direct and indirect interactions influence the motion of filaments. A monotonic increase of filament peak velocity with upstream electron temperature is observed, while a decrease with increasing electron density is observed. If ordered by the target temperature, the density dependence disappears and the filament velocityis only a function of the target temperature. Smaller filaments keep a density dependence, as a result of the density dependence of the plasma viscosity. The critical size δ∗, where filaments are fastest, is shifted to larger sizes for higher densities, due to the plasma viscosity. If the density dependence of the plasma viscosity is removed, δ∗ has no density dependence, but rather a temperature dependence.

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