Fractional Transport in Strongly Turbulent Plasmas

Area of Science:

• Plasma physics
• Astrophysics
• Computational physics

Background:

• Particle energization is crucial in astrophysical and space plasmas.
• Turbulent environments with current filaments are common in space plasmas.
• Classical transport models may not capture complex energization processes.

Purpose of the Study:

• To investigate particle energization in a simulated turbulent, filamentary environment.
• To assess the validity of the classical Fokker-Planck equation for particle transport.
• To develop and validate a fractional transport equation for anomalous energy diffusion.

Main Methods:

• 3D resistive magnetohydrodynamics simulations to generate turbulent plasma.
• Test-particle simulations to track particle dynamics.
• Statistical analysis of particle energy distributions.
• Derivation and parameterization of a fractional transport equation.

Main Results:

• The classical Fokker-Planck equation fails to reproduce simulation results.
• Particle energization exhibits anomalous transport, characterized by Levy flights.
• Energy distributions show extended power-law tails.
• The derived fractional transport equation accurately models the high-energy particle distributions.

Conclusions:

• Anomalous transport, not classical diffusion, governs particle energization in this turbulent regime.
• Fractional transport equations are essential for accurately describing Levy flights and power-law tails in particle energy.
• The choice between Fokker-Planck and fractional transport equations depends on simulation data analysis.