Plasma blob formation by ion kinetic Kelvin–Helmholtz and interchange instabilities
Plasma blob formation by ion kinetic Kelvin–Helmholtz and interchange instabilities
The near-edge region of a tokamak is observed to generate radially propagating, coherent filamentary structures ('blobs'), which transport particles and heat from the confined region and across the scrape-off layer. The distribution of blob sizes may include a currently unresolvable population with radii comparable to the ion gyro-radius. Here, we conduct large-scale numerical simulations to study mechanisms for the creation of ion gyro-scale blobs via the ion kinetic Kelvin–Helmholtz and interchange instabilities, using a hybrid (kinetic ion, fluid electron) model. We present statistics of the sizes of blobs created by these instabilities, and radial particle displacement data. We find that ion gyro-scale blobs constitute a significant portion of the blob population, and that an increase in ion gyro-radius results in an increase in radial transport. Results are contrasted for pure proton plasmas and for 50 : 50 deuterium–tritium mix, relevant to burning plasmas. We conclude that ion kinetic physics plays a significant role in the transport of energy and particles by ion gyro-scale blobs in the near-edge region of low-field tokamaks.
Gingell, P W
ba7b8113-3833-40d8-a879-aab3f987455d
Chapman, S C
c5394452-86aa-4b1d-b0bd-8c1ee24a4eeb
Dendy, R O
f8778d5b-e9e1-47ee-88f3-a63fa4fa2766
1 March 2014
Gingell, P W
ba7b8113-3833-40d8-a879-aab3f987455d
Chapman, S C
c5394452-86aa-4b1d-b0bd-8c1ee24a4eeb
Dendy, R O
f8778d5b-e9e1-47ee-88f3-a63fa4fa2766
Gingell, P W, Chapman, S C and Dendy, R O
(2014)
Plasma blob formation by ion kinetic Kelvin–Helmholtz and interchange instabilities.
Plasma Physics and Controlled Fusion, 56 (3), [035012].
(doi:10.1088/0741-3335/56/3/035012).
Abstract
The near-edge region of a tokamak is observed to generate radially propagating, coherent filamentary structures ('blobs'), which transport particles and heat from the confined region and across the scrape-off layer. The distribution of blob sizes may include a currently unresolvable population with radii comparable to the ion gyro-radius. Here, we conduct large-scale numerical simulations to study mechanisms for the creation of ion gyro-scale blobs via the ion kinetic Kelvin–Helmholtz and interchange instabilities, using a hybrid (kinetic ion, fluid electron) model. We present statistics of the sizes of blobs created by these instabilities, and radial particle displacement data. We find that ion gyro-scale blobs constitute a significant portion of the blob population, and that an increase in ion gyro-radius results in an increase in radial transport. Results are contrasted for pure proton plasmas and for 50 : 50 deuterium–tritium mix, relevant to burning plasmas. We conclude that ion kinetic physics plays a significant role in the transport of energy and particles by ion gyro-scale blobs in the near-edge region of low-field tokamaks.
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Accepted/In Press date: 27 January 2014
e-pub ahead of print date: 18 February 2014
Published date: 1 March 2014
Identifiers
Local EPrints ID: 438488
URI: http://eprints.soton.ac.uk/id/eprint/438488
ISSN: 0741-3335
PURE UUID: 5585f444-bb9c-41e1-a2ef-62e4a6919924
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Date deposited: 11 Mar 2020 17:31
Last modified: 17 Mar 2024 03:59
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Author:
S C Chapman
Author:
R O Dendy
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