The response of toroidal drift modes to profile evolution: A model for small-ELMs in tokamak plasmas?

A. Bokshi; D. Dickinson; C. M. Roach; H. R. Wilson

doi:10.1088/0741-3335/58/7/075011

The response of toroidal drift modes to profile evolution: A model for small-ELMs in tokamak plasmas?

A. Bokshi, D. Dickinson, C. M. Roach, H. R. Wilson

Physics

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

Abstract

We consider a time-dependent linear global electrostatic toroidal fluid ion-temperature gradient (ITG) model to study the evolution of toroidal drift modes in tokamak plasmas as the equilibrium flow-shear varies with time. While we consider the ITG mode as a specific example, the results are expected to be valid for most other toroidal microinstabilities. A key result is that when there is a position in the plasma with a maximum in the instability drive (e.g. ITG), there is a transient burst of stronger growth as the flow-shear evolves through a critical value. This transient burst is expected to drive a filamentary plasma eruption, reminiscent of small-ELMs. The amplitude of the dominant linear mode is initially peaked above or below the outboard midplane, and rotates through it poloidally as the flow-shear passes through the critical value. This theoretical prediction could provide an experimental test of whether this mechanism underlies some classes of small-ELMs.

Original language	English
Article number	075011
Pages (from-to)	1-13
Number of pages	13
Journal	Plasma Physics and Controlled Fusion
Volume	58
Issue number	7
DOIs	https://doi.org/10.1088/0741-3335/58/7/075011
Publication status	Published - 3 Jun 2016

Bibliographical note

© 2016 IOP Publishing Ltd. 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. Embargo period : 12 months

Keywords

ballooning formalism
Floquet modes
small ELMs
toroidal drift modes

Access to Document

10.1088/0741-3335/58/7/075011

Bokshi PPCF 2016
© 2016 IOP Publishing Ltd. 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. Embargo period : 12 months
Accepted author manuscript, 3.24 MB

Cite this

@article{3624ce695ff84ac19544ba1f720482ff,

title = "The response of toroidal drift modes to profile evolution: A model for small-ELMs in tokamak plasmas?",

abstract = "We consider a time-dependent linear global electrostatic toroidal fluid ion-temperature gradient (ITG) model to study the evolution of toroidal drift modes in tokamak plasmas as the equilibrium flow-shear varies with time. While we consider the ITG mode as a specific example, the results are expected to be valid for most other toroidal microinstabilities. A key result is that when there is a position in the plasma with a maximum in the instability drive (e.g. ITG), there is a transient burst of stronger growth as the flow-shear evolves through a critical value. This transient burst is expected to drive a filamentary plasma eruption, reminiscent of small-ELMs. The amplitude of the dominant linear mode is initially peaked above or below the outboard midplane, and rotates through it poloidally as the flow-shear passes through the critical value. This theoretical prediction could provide an experimental test of whether this mechanism underlies some classes of small-ELMs.",

keywords = "ballooning formalism, Floquet modes, small ELMs, toroidal drift modes",

author = "A. Bokshi and D. Dickinson and Roach, {C. M.} and Wilson, {H. R.}",

note = "{\textcopyright} 2016 IOP Publishing Ltd. This is an author-produced version of the published paper. Uploaded in accordance with the publisher{\textquoteright}s self-archiving policy. Further copying may not be permitted; contact the publisher for details. Embargo period : 12 months ",

year = "2016",

month = jun,

day = "3",

doi = "10.1088/0741-3335/58/7/075011",

language = "English",

volume = "58",

pages = "1--13",

journal = "Plasma Physics and Controlled Fusion",

issn = "0741-3335",

publisher = "IOP Publishing",

number = "7",

}

TY - JOUR

T1 - The response of toroidal drift modes to profile evolution

T2 - A model for small-ELMs in tokamak plasmas?

AU - Bokshi, A.

AU - Dickinson, D.

AU - Roach, C. M.

AU - Wilson, H. R.

N1 - © 2016 IOP Publishing Ltd. 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. Embargo period : 12 months

PY - 2016/6/3

Y1 - 2016/6/3

N2 - We consider a time-dependent linear global electrostatic toroidal fluid ion-temperature gradient (ITG) model to study the evolution of toroidal drift modes in tokamak plasmas as the equilibrium flow-shear varies with time. While we consider the ITG mode as a specific example, the results are expected to be valid for most other toroidal microinstabilities. A key result is that when there is a position in the plasma with a maximum in the instability drive (e.g. ITG), there is a transient burst of stronger growth as the flow-shear evolves through a critical value. This transient burst is expected to drive a filamentary plasma eruption, reminiscent of small-ELMs. The amplitude of the dominant linear mode is initially peaked above or below the outboard midplane, and rotates through it poloidally as the flow-shear passes through the critical value. This theoretical prediction could provide an experimental test of whether this mechanism underlies some classes of small-ELMs.

AB - We consider a time-dependent linear global electrostatic toroidal fluid ion-temperature gradient (ITG) model to study the evolution of toroidal drift modes in tokamak plasmas as the equilibrium flow-shear varies with time. While we consider the ITG mode as a specific example, the results are expected to be valid for most other toroidal microinstabilities. A key result is that when there is a position in the plasma with a maximum in the instability drive (e.g. ITG), there is a transient burst of stronger growth as the flow-shear evolves through a critical value. This transient burst is expected to drive a filamentary plasma eruption, reminiscent of small-ELMs. The amplitude of the dominant linear mode is initially peaked above or below the outboard midplane, and rotates through it poloidally as the flow-shear passes through the critical value. This theoretical prediction could provide an experimental test of whether this mechanism underlies some classes of small-ELMs.

KW - ballooning formalism

KW - Floquet modes

KW - small ELMs

KW - toroidal drift modes

UR - http://www.scopus.com/inward/record.url?scp=84976325890&partnerID=8YFLogxK

U2 - 10.1088/0741-3335/58/7/075011

DO - 10.1088/0741-3335/58/7/075011

M3 - Article

AN - SCOPUS:84976325890

SN - 0741-3335

VL - 58

SP - 1

EP - 13

JO - Plasma Physics and Controlled Fusion

JF - Plasma Physics and Controlled Fusion

IS - 7

M1 - 075011

ER -

The response of toroidal drift modes to profile evolution: A model for small-ELMs in tokamak plasmas?

Abstract

Bibliographical note

Keywords

Access to Document

Other files and links

David Dickinson