AUTHOR=Nakanotani Masaru , Zank Gary P. , Zhao Lingling 

TITLE=Particle acceleration in an MHD-scale system of multiple current sheets

JOURNAL=Frontiers in Astronomy and Space Sciences

VOLUME=9

YEAR=2022

URL=https://www.frontiersin.org/journals/astronomy-and-space-sciences/articles/10.3389/fspas.2022.954040

DOI=10.3389/fspas.2022.954040

ISSN=2296-987X

ABSTRACT=<p>We investigate particle acceleration in an MHD-scale system of multiple current sheets by performing 2D and 3D MHD simulations combined with a test particle simulation. The system is unstable for the tearing-mode instability, and magnetic islands are produced by magnetic reconnection. Due to the interaction of magnetic islands, the system relaxes to a turbulent state. The 2D (3D) case both yield −5/3 (− 11/3 and −7/3) power-law spectra for magnetic and velocity fluctuations. Particles are efficiently energized by the generated turbulence, and form a power-law tail with an index of −2.2 and −4.2 in the energy distribution function for the 2D and 3D case, respectively. We find more energetic particles outside magnetic islands than inside. We observe super-diffusion in the 2D (∼ <italic>t</italic><sup>2.27</sup>) and 3D (∼ <italic>t</italic><sup>1.2</sup>) case in the energy space of energetic particles.</p>