Collision-dependent power law scalings in 2D gyrokinetic turbulence
arXiv:1405.5375 · doi:10.1063/1.4892347
Abstract
Nonlinear gyrokinetics provides a suitable framework to describe short-wavelength turbulence in magnetized laboratory and astrophysical plasmas. In the electrostatic limit, this system is known to exhibit a free energy cascade towards small scales in (perpendicular) real and/or velocity space. The dissipation of free energy is always due to collisions (no matter how weak the collisionality), but may be spread out across a wide range of scales. Here, we focus on freely-decaying 2D electrostatic turbulence on sub-ion-gyroradius scales. An existing scaling theory for the turbulent cascade in the weakly collisional limit is generalized to the moderately collisional regime. In this context, non-universal power law scalings due to multiscale dissipation are predicted, and this prediction is confirmed by means of direct numerical simulations.
arXiv comment7 pages, 5 figures, accepted for publication in Physics of Plasmas
References in corpus (8)
- Astrophysical gyrokinetics: kinetic and fluid turbulent cascades in magnetized weakly collisional plasmas
- Linearized model Fokker-Planck collision operators for gyrokinetic simulations. I. Theory
- Nonlinear phase mixing and phase-space cascade of entropy in gyrokinetic plasma turbulence
- Gyrokinetic turbulence: a nonlinear route to dissipation through phase space
- Linearized model Fokker-Planck collision operators for gyrokinetic simulations. II. Numerical implementation and tests
- Two-dimensional gyrokinetic turbulence
- The energetic coupling of scales in gyrokinetic plasma turbulence
- Free energy cascade in gyrokinetic turbulence