Helical Fluid and (Hall)-MHD Turbulence: a Brief Review
arXiv:2104.12855 · doi:10.1098/rsta.2021.0087
Abstract
Helicity, a measure of the breakage of reflectional symmetry representing the topology of turbulent flows, contributes in a crucial way to their dynamics and to their fundamental statistical properties. We review several of their main features, both new and old, as the discovery of bi-directional cascades or the role of helical vortices in the enhancement of large-scale magnetic fields in the dynamo problem. The dynamical contribution in magnetohydrodynamic (MHD) of the cross-correlation between velocity and induction is discussed as well. We consider next how turbulent transport is affected by helical constraints, in particular in the context of magnetic reconnection and fusion plasmas {under one- and two-fluid approximations}. Central issues on how to construct turbulence models for non-reflectionally symmetric helical flows are reviewed, including in the presence of shear, and we finally briefly mention the possible role of helicity in the development of strongly localized quasi-singular structures {at small scale).
14 pages, 0 figure 0 table
References in corpus (11)
- Observation of inertial energy cascade in interplanetary space plasma
- On the von Karman-Howarth equations for Hall MHD flows
- Turbulence-driven ion beams in the magnetospheric Kelvin-Helmholtz instability
- Non-local interactions in hydrodynamic turbulence at high Reynolds numbers: the slow emergence of scaling laws
- Helicity cascades in rotating turbulence
- On energy conservation in extended magnetohydrodynamics
- Dual cascade and dissipation mechanisms in helical quantum turbulence
- Vortex knots in tangled quantum eigenfunctions
- On the structure and statistical theory of turbulence of extended magnetohydrodynamics
- Modeling imbalanced collisionless Alfvén wave turbulence with nonlinear diffusion equations
- Dynamic Phase Alignment in Navier-Stokes Turbulence