Dynamics of zonal flow saturation in strong collisionless drift wave turbulence

Eun Jin Kim, P. H. Diamond

Research output: Contribution to journalArticle

55 Citations (Scopus)

Abstract

Generalized Kelvin–Helmholtz (GKH) instability is examined as a mechanism for the saturation of zonal flows in the collisionless regime. By focusing on strong turbulence regimes, GKH instability is analyzed in the presence of a background of finite-amplitude drift waves. A detailed study of a simple model with cold ions shows that nonlinear excitation of GKH modes via modulational instability can be comparable to their linear generation. Furthermore, it is demonstrated that zonal flows are likely to grow faster than GKH mode near marginality, with insignificant turbulent viscous damping by linear GKH. The effect of finite ion temperature fluctuations is incorporated in a simple toroidal ion temperature gradient model, within which both zonal flow and temperature are generated by modulational instability. The phase between the two is calculated self-consistently and shown to be positive. Furthermore, the correction to nonlinear generation of GKH modes appears to be small, being of order O(ρ2ik2). Thus, the role of linear GKH instability in the saturation of collisionless zonal flows, in general, seems dubious.
Original languageEnglish
Pages (from-to)4530
Number of pages1
JournalPhysics of Plasmas
Volume9
Issue number11
DOIs
Publication statusPublished - 23 Oct 2002
Externally publishedYes

Fingerprint

turbulence
saturation
ion temperature
viscous damping
temperature gradients
excitation
ions
temperature

ASJC Scopus subject areas

  • Physics and Astronomy(all)
  • Condensed Matter Physics

Cite this

Dynamics of zonal flow saturation in strong collisionless drift wave turbulence. / Kim, Eun Jin; Diamond, P. H.

In: Physics of Plasmas, Vol. 9, No. 11, 23.10.2002, p. 4530.

Research output: Contribution to journalArticle

@article{bb88e53b3fd94587bbaac70657543afc,
title = "Dynamics of zonal flow saturation in strong collisionless drift wave turbulence",
abstract = "Generalized Kelvin–Helmholtz (GKH) instability is examined as a mechanism for the saturation of zonal flows in the collisionless regime. By focusing on strong turbulence regimes, GKH instability is analyzed in the presence of a background of finite-amplitude drift waves. A detailed study of a simple model with cold ions shows that nonlinear excitation of GKH modes via modulational instability can be comparable to their linear generation. Furthermore, it is demonstrated that zonal flows are likely to grow faster than GKH mode near marginality, with insignificant turbulent viscous damping by linear GKH. The effect of finite ion temperature fluctuations is incorporated in a simple toroidal ion temperature gradient model, within which both zonal flow and temperature are generated by modulational instability. The phase between the two is calculated self-consistently and shown to be positive. Furthermore, the correction to nonlinear generation of GKH modes appears to be small, being of order O(ρ2ik2). Thus, the role of linear GKH instability in the saturation of collisionless zonal flows, in general, seems dubious.",
author = "Kim, {Eun Jin} and Diamond, {P. H.}",
year = "2002",
month = "10",
day = "23",
doi = "10.1063/1.1514641",
language = "English",
volume = "9",
pages = "4530",
journal = "Physics of Plasmas",
issn = "1070-664X",
publisher = "AIP Publishing",
number = "11",

}

TY - JOUR

T1 - Dynamics of zonal flow saturation in strong collisionless drift wave turbulence

AU - Kim, Eun Jin

AU - Diamond, P. H.

PY - 2002/10/23

Y1 - 2002/10/23

N2 - Generalized Kelvin–Helmholtz (GKH) instability is examined as a mechanism for the saturation of zonal flows in the collisionless regime. By focusing on strong turbulence regimes, GKH instability is analyzed in the presence of a background of finite-amplitude drift waves. A detailed study of a simple model with cold ions shows that nonlinear excitation of GKH modes via modulational instability can be comparable to their linear generation. Furthermore, it is demonstrated that zonal flows are likely to grow faster than GKH mode near marginality, with insignificant turbulent viscous damping by linear GKH. The effect of finite ion temperature fluctuations is incorporated in a simple toroidal ion temperature gradient model, within which both zonal flow and temperature are generated by modulational instability. The phase between the two is calculated self-consistently and shown to be positive. Furthermore, the correction to nonlinear generation of GKH modes appears to be small, being of order O(ρ2ik2). Thus, the role of linear GKH instability in the saturation of collisionless zonal flows, in general, seems dubious.

AB - Generalized Kelvin–Helmholtz (GKH) instability is examined as a mechanism for the saturation of zonal flows in the collisionless regime. By focusing on strong turbulence regimes, GKH instability is analyzed in the presence of a background of finite-amplitude drift waves. A detailed study of a simple model with cold ions shows that nonlinear excitation of GKH modes via modulational instability can be comparable to their linear generation. Furthermore, it is demonstrated that zonal flows are likely to grow faster than GKH mode near marginality, with insignificant turbulent viscous damping by linear GKH. The effect of finite ion temperature fluctuations is incorporated in a simple toroidal ion temperature gradient model, within which both zonal flow and temperature are generated by modulational instability. The phase between the two is calculated self-consistently and shown to be positive. Furthermore, the correction to nonlinear generation of GKH modes appears to be small, being of order O(ρ2ik2). Thus, the role of linear GKH instability in the saturation of collisionless zonal flows, in general, seems dubious.

UR - http://www.scopus.com/inward/record.url?scp=0036856860&partnerID=8YFLogxK

U2 - 10.1063/1.1514641

DO - 10.1063/1.1514641

M3 - Article

VL - 9

SP - 4530

JO - Physics of Plasmas

JF - Physics of Plasmas

SN - 1070-664X

IS - 11

ER -