Transition from Vortical to Alfvénic-like Fermi Electron Acceleration in Magnetic Reconnection with Increasing Guide Field
Year: 2025
Type: article
Abstract: Using particle-in-cell simulations of magnetic reconnection (MR), we investigate how the changing magnetic guide field strength impacts the evolution of electron Kelvin–Helmholtz instability (EKHI) and the associated Fermi electron acceleration proposed by H. Che & G. P. Zank. Through this investigation, an Alfvénic-like Fermi electron acceleration mechanism is discovered for strong guide field MR B g /B 0 > 2.5, where B g is the magnetic guide field. The electrons are accelerated by the intensive electric potential produced through δ U i × B , where the ion velocity fluctuations δ U i propagate parallel to the direction of the Alfvén-like waves. Differing from the two-stage second-order Fermi acceleration produced by the stochastic electric field of EKHI, the Alfvén-like wave mechanism is a much more efficient one-stage process that produces a much harder power-law electron energy spectrum, with an index ∼2, than that of the EKHI, with an index ∼4.
Source: The Astrophysical Journal
Authors: C. Crawford, H. Che, G. P. Zank, A. O. Benz
Language: English
Subfield: Astronomy and Astrophysics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: gold
Estimated APC paid: $4,499
OpenAlex ID: W4409440427