Abstract
Abstract Magnetic reconnection is widely accepted to be a major contributor to nonthermal particle acceleration in the solar atmosphere. In this paper we investigate particle acceleration during the impulsive phase of a coronal jet, which involves bursty reconnection at a magnetic null point. A test-particle approach is employed, using electromagnetic fields from a magnetohydrodynamic simulation of such a jet. Protons and electrons are found to be accelerated nonthermally both downwards toward the domain’s lower boundary and the solar photosphere, and outwards along the axis of the coronal jet and into the heliosphere. A key finding is that a circular ribbon of particle deposition on the photosphere is predicted, with the protons and electrons concentrated in different parts of the ribbon. Furthermore, the outgoing protons and electrons form two spatially separated beams parallel to the axis of the jet, signatures that may be observable in in-situ observations of the heliosphere.
Highlights
Explosive energy conversion occurs on a broad range of scales in the solar corona from nanoflares to large X-class flares
Magnetic reconnection plays a critical role in rapidly converting stored magnetic energy into thermal and kinetic energy, as well as the energy associated with nonthermally accelerated particles
Among the ubiquitous phenomena observed on the Sun are coronal jets: collimated ejections of plasma launched by the impulsive onset of reconnection low in the solar atmosphere
Summary
Explosive energy conversion occurs on a broad range of scales in the solar corona from nanoflares to large X-class flares. We use the test-particle approach, whereby a large number of individual noninteracting charged particles are placed in electromagnetic fields derived from the simulation to produce spatial ejecta patterns and kinetic energy distributions (such as those discussed by Li et al 2021) This test-particle approach has been widely used for probing particle acceleration in the corona. We venture well beyond all of these previous results by modeling a jet in which the reconnection process is bursty, occurs in a fragmented region, and connects magnetically to remote parts of the solar atmosphere. These features are much more typical of an impulsively driven reconnection event in the corona (e.g., Ji & Daughton 2011).
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