Dynamic Phase Alignment in Inertial Alfvén Turbulence

Area of Science:

• Plasma Physics
• Astrophysics
• Geophysics

Background:

• Alfvénic turbulence is prevalent in weakly collisional plasmas.
• At small scales (below electron skin depth), it transforms into inertial Alfvénic turbulence.

Purpose of the Study:

• To investigate the cascade dynamics of energy and generalized kinetic helicity in inertial Alfvénic turbulence.
• To determine the compatibility and scaling laws of these dual cascades.

Main Methods:

• Theoretical analysis of turbulence in magnetized plasmas.
• Examination of spectral energy and helicity transfer.
• Derivation of scaling laws for phase alignment and anisotropy.

Main Results:

• Energy and generalized kinetic helicity exhibit direct cascades in inertial Alfvénic turbulence.
• Phase alignment between velocity and magnetic field fluctuations scales as cosα_{k}∝k_{⊥}^{-1}.
• Kinetic and magnetic energy spectra scale as ∝k_{⊥}^{-5/3} and ∝k_{⊥}^{-11/3}, respectively.
• Generalized helicity spectrum scales as ∝k_{⊥}^{-5/3}, indicating turbulence balancing at smaller scales.
• Turbulent eddies show phase-space anisotropy k_{∥}∝k_{⊥}^{5/3}.

Conclusions:

• The dual direct cascade of energy and generalized kinetic helicity is compatible in inertial Alfvénic turbulence.
• These findings explain critically balanced inertial Alfvén fluctuations.
• The results have broad applicability in space, astrophysical, and geophysical plasma environments.