Freely decaying turbulence in two-dimensional electrostatic gyrokinetics

T Tatsuno; G. G Plunk; M Barnes; W Dorland; G. G Howes; R Numata

doi:10.1063/1.4769029

Back

Freely decaying turbulence in two-dimensional electrostatic gyrokinetics

Journal article

Peer reviewed

Freely decaying turbulence in two-dimensional electrostatic gyrokinetics

T Tatsuno, G. G Plunk, M Barnes, W Dorland, G. G Howes and R Numata

Physics of plasmas, Vol.19(12), p.122305

12/15/2012

DOI: 10.1063/1.4769029

Files and links (1)

url

https://arxiv.org/pdf/1208.1369View

Open Access

Abstract

In magnetized plasmas, a turbulent cascade occurs in phase space at scales smaller than the thermal Larmor radius ('sub-Larmor scales') [Tatsuno et al., Phys. Rev. Lett. 103, 015003 (2009)]. When the turbulence is restricted to two spatial dimensions perpendicular to the background magnetic field, two independent cascades may take place simultaneously because of the presence of two collisionless invariants. In the present work, freely decaying turbulence of two-dimensional electrostatic gyrokinetics is investigated by means of phenomenological theory and direct numerical simulations. A dual cascade (forward and inverse cascades) is observed in velocity space as well as in position space, which we diagnose by means of nonlinear transfer functions for the collisionless invariants. We find that the turbulence tends to a time-asymptotic state, dominated by a single scale that grows in time. A theory of this asymptotic state is derived in the form of decay laws. Each case that we study falls into one of three regimes (weakly collisional, marginal, and strongly collisional), determined by a dimensionless number D{sub *}, a quantity analogous to the Reynolds number. The marginal state is marked by a critical number D{sub *}=D{sub 0} that is preserved in time. Turbulence initialized above this value become increasingly inertial in time, evolving toward larger and larger D{sub *}; turbulence initialized below D{sub 0} become more and more collisional, decaying to progressively smaller D{sub *}.

Turbulence

70 PLASMA PHYSICS AND FUSION TECHNOLOGY

ASYMPTOTIC SOLUTIONS

CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS

COMPUTERIZED SIMULATION

LARMOR RADIUS

MAGNETIC FIELDS

NONLINEAR PROBLEMS

PHASE SPACE

PLASMA

REYNOLDS NUMBER

TRANSFER FUNCTIONS

TWO-DIMENSIONAL CALCULATIONS

Details

Title: Subtitle: Freely decaying turbulence in two-dimensional electrostatic gyrokinetics
Creators: T Tatsuno - University of Maryland, College Park
G. G Plunk - Max Planck Society
M Barnes - University of Maryland, College Park
W Dorland - University of Maryland, College Park
G. G Howes - University of Maryland, College Park
R Numata - University of Maryland, College Park
Resource Type: Journal article
Publication Details: Physics of plasmas, Vol.19(12), p.122305
DOI: 10.1063/1.4769029
ISSN: 1070-664X
eISSN: 1089-7674
Grant note: DOI: 10.13039/100000015, name: U.S. Department of Energy, award: 24540533
Language: English
Date published: 12/15/2012
Academic Unit: Physics and Astronomy
Record Identifier: 9984199782002771

Metrics

4 Record Views

8 Times Cited - Web of Science