Super-Fermi Acceleration in Multiscale MHD Reconnection

Abstract

We investigate the Fermi acceleration of charged particles in 2D MHD anti-parallel plasmoid reconnection, finding a drastic enhancement in energization rate $\dot{\epsilon }$ over a standard Fermi model of $\dot{\epsilon }\sim \epsilon$. The shrinking particle orbit width around a magnetic island due to $\vec{E}\times \vec{B}$ drift produces a ${\dot{\epsilon }}_{\parallel }\sim {\epsilon }_{\parallel }^{1+1/2\chi }$ power law with $\chi \sim 0.75$. The increase in the maximum possible energy gain of a particle within a plasmoid due to the enhanced efficiency increases with the plasmoid size, and is by multiple factors of 10 in the case of solar flares and much more for larger plasmas. Including effects of the non-constant $\vec{E}\times \vec{B}$ drift rates leads to further variation of power law indices from $\gtrsim 2$ to $\lesssim 1$, decreasing with plasmoid size at the time of injection.

arXiv comment7 pages, 7 figures

References in corpus (33)

• Relativistic Reconnection: an Efficient Source of Non-Thermal Particles
• Formation of Hard Power-laws in the Energetic Particle Spectra Resulting from Relativistic Magnetic Reconnection
• Astrophysical Gyrokinetics: Basic Equations and Linear Theory
• The Generation of Nonthermal Particles in the Relativistic Magnetic Reconnection of Pair Plasmas
• Scaling laws of resistive magnetohydrodynamic reconnection in the high-Lundquist-number, plasmoid-unstable regime
• The Mechanisms of Electron Heating and Acceleration during Magnetic Reconnection
• Phase Diagram for Magnetic Reconnection in Heliophysical, Astrophysical and Laboratory Plasmas
• Magnetic reconnection and stochastic plasmoid chains in high-Lundquist-number plasmas
• Plasmoids in relativistic reconnection, from birth to adulthood: first they grow, then they go
• Measurement of magnetic field and relativistic electrons along a solar flare current sheet
• Electron Acceleration during Macroscale Magnetic Reconnection
• Magnetic reconnection in the era of exascale computing and multiscale experiments
• Magnetic Reconnection in Extreme Astrophysical Environments
• Parallel electric fields are inefficient drivers of energetic electrons in magnetic reconnection
• Pulsar Radio Emission Mechanism: Radio Nanoshots as a Low Frequency Afterglow of Relativistic Magnetic Reconnection
• On the Distribution of Plasmoids In High-Lundquist-Number Magnetic Reconnection
• Formation of Power-law Electron Energy Spectra in Three-dimensional Low-$\beta$ Magnetic Reconnection
• Recent Progress on Particle Acceleration and Reconnection Physics during Magnetic Reconnectionin the Magnetically-dominated Relativistic Regime
• Determining the Dominant Acceleration Mechanism during Relativistic Magnetic Reconnection in Large-scale Systems
• Secondary Energization in Compressing Plasmoids during Magnetic Reconnection
• Particle Injection and Nonthermal Particle Acceleration in Relativistic Magnetic Reconnection
• First-principles Fermi acceleration in magnetized turbulence
• Multi-scale dynamics of magnetic flux tubes and inverse magnetic energy transfer
• Exploring the acceleration mechanisms for particle injection and power-law formation during trans-relativistic magnetic reconnection
• Direct measurement of non-thermal electron acceleration from magnetically driven reconnection in a laboratory plasma
• Reconnection and particle acceleration in interacting flux ropes I. Magnetohydrodynamics and test particles in 2.5D
• A model of Hall reconnection
• Measurements of Coronal Magnetic Field Strengths in Solar Active Region Loops
• The Mechanism of Electron Injection and Acceleration in Trans-Relativistic Reconnection
• Large-Scale Parallel Electric Fields and Return Currents in a Global Simulation Model
• Plasmoid-dominated Turbulent Reconnection in a Low $\beta$ Plasma
• Guide Field Effects on the Distribution of Plasmoids in Multiple Scale Reconnection
• Non-ideal fields solve the injection problem in relativistic reconnection

Cited by in corpus (1)

• Particle injection in three-dimensional relativistic magnetic reconnection