Initiation of Alfvénic turbulence by Alfven wave collisions: A numerical study

Abstract

In the framework of compressional magnetohydrodynamics (MHD), we numerically studied the commonly accepted presumption that the Alfvénic turbulence is generated by the collisions between counter-propagating Alfvén waves (AWs). In the conditions typical for the low-beta solar corona and inner solar wind, we launched two counter-propagating AWs in the three-dimensional simulation box and analyzed polarization and spectral properties of perturbations generated before and after AW collisions. The observed post-collisional perturbations have different polarizations and smaller cross-field scales than the original waves, which supports theoretical scenarios with direct turbulent cascades. However, contrary to theoretical expectations, the spectral transport is strongly suppressed at the scales satisfying the classic critical balance of incompressional MHD. Instead, a modified critical balance can be established by colliding AWs with significantly shorter perpendicular scales. We discuss consequences of these effects for the turbulence dynamics and turbulent heating of compressional plasmas. In particular, solar coronal loops can be heated by the strong turbulent cascade if the characteristic widths of the loop substructures are more than ten times smaller than the loop width. The revealed new properties of AW collisions have to be incorporated in the theoretical models of AW turbulence and related applications.

arXiv comment9 pages, 9 figures

References in corpus (25)

• A weak turbulence theory for incompressible MHD
• MPI-AMRVAC for Solar and Astrophysics
• Role of cross helicity in magnetohydrodynamic turbulence
• Strong Imbalanced Turbulence
• Turbulent kinetic energy in the energy balance of a solar flare
• Alfven Wave Collisions, The Fundamental Building Block of Plasma Turbulence I: Asymptotic Solution
• A Population of X-ray Weak Quasars: PHL 1811 Analogs at High Redshift
• A global view of velocity fluctuations in the corona below 1.3 $R_{\odot }$ with CoMP
• Reflection-driven MHD turbulence in the solar atmosphere and solar wind
• Spectra of strong MHD Turbulence from high-resolution simulations
• Refined critical balance in strong Alfvenic turbulence
• Measurements of Non-Thermal Line Widths in Solar Active Regions
• Phase Mixing of Nonlinear Visco-resistive Alfvén Waves
• Coronal heating in coupled photosphere-chromosphere-coronal systems: turbulence and leakage
• Alfven Wave Collisions, The Fundamental Building Block of Plasma Turbulence II: Numerical Solution
• Colliding Alfvénic wave packets in MHD, Hall and kinetic simulations
• On the parallel spectrum in MHD Turbulence
• Plasma parameters and geometry of cool and warm active region loops
• Alfven Wave Collisions, The Fundamental Building Block of Plasma Turbulence IV: Laboratory Experiment
• Nonlinear evolution of short-wavelength torsional Alfven waves
• Nonlinear energy transfer and current sheet development in localized Alfven wavepacket collisions in the strong turbulence limit
• The nature of Elsässer variables in compressible MHD
• The Alfvenic nature of energy transfer mediation in localized, strongly nonlinear Alfven wavepacket collisions
• Exploring the damping of Alfvén waves along a long off-limb coronal loop, up to 1.4 R${}_{\odot }$
• Analysis of Magnetic Fields in Inertial Alfven Wave Collisions