Test-particle acceleration in a hierarchical three-dimensional turbulence model

Abstract

The acceleration of charged particles is relevant to the solar corona over a broad range of scales and energies. High-energy particles are usually detected in concomitance with large energy release events like solar eruptions and flares, nevertheless acceleration can occur at smaller scales, characterized by dynamical activity near current sheets. To gain insight into the complex scenario of coronal charged particle acceleration, we investigate the properties of acceleration with a test-particle approach using three-dimensional magnetohydrodynamic (MHD) models. These are obtained from direct solutions of the reduced MHD equations, well suited for a plasma embedded in a strong axial magnetic field, relevant to the inner heliosphere. A multi-box, multi-scale technique is used to solve the equations of motion for protons. This method allows us to resolve an extended range of scales present in the system, namely from the ion inertial scale of the order of a meter up to macroscopic scales of the order of $10$km ($1/100$th of the outer scale of the system). This new technique is useful to identify the mechanisms that, acting at different scales, are responsible for acceleration to high energies of a small fraction of the particles in the coronal plasma. We report results that describe acceleration at different stages over a broad range of time, length and energy scales.

12 pages, 8 figures, ApJ (in press)

References in corpus (6)

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Cited by in corpus (21)

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• Laboratory Space Physics: Investigating the Physics of Space Plasmas in the Laboratory
• Ion and Electron Acceleration in Fully Kinetic Plasma Turbulence
• Particle acceleration in relativistic turbulence: A theoretical appraisal
• Properties of the First-order Fermi acceleration in fast magnetic reconnection driven by turbulence in collisional MHD flows
• Relativistic Particle Transport and Acceleration in Structured Plasma Turbulence
• Powerlaw spectra from stochastic acceleration
• Plasma compression in magnetic reconnection regions in the solar corona
• Two-stage electron acceleration by 3D collisionless guide field magnetic reconnection
• Coronal Heating Topology: the Interplay of Current Sheets and Magnetic Field Lines
• Test particle energization and the anisotropic effects of dynamical MHD turbulence
• On the compressibility effect in test particle acceleration by magnetohydrodynamic turbulence
• Neoclassical Pitch-Angle Scattering of Runaway Electrons
• Turbulence and particle energization in twisted flux ropes in solar-wind conditions
• Acceleration of Particles in Imbalanced Magnetohydrodynamic Turbulence
• Test particle energization of heavy ions in magnetohydrodynamic turbulence
• Current sheets, plasmoids and flux ropes in the heliosphere. Part II: Theoretical aspects
• Non-ideal fields solve the injection problem in relativistic reconnection