Fast Acceleration of Transrelativistic Electrons in Astrophysical Turbulence

0538382 - ÚFA 2021 RIV US eng J - Journal Article
Trotta, D. - Franci, L. - Burgess, D. - Hellinger, Petr
Fast Acceleration of Transrelativistic Electrons in Astrophysical Turbulence.
Astrophysical Journal. Roč. 894, č. 2 (2020), č. článku 136. ISSN 0004-637X. E-ISSN 1538-4357
Institutional support: RVO:68378289
Keywords : interplanetary particle acceleration * interplanetary turbulence * plasma astrophysics
OECD category: Astronomy (including astrophysics,space science)
Impact factor: 5.877, year: 2020
Method of publishing: Open access
https://arxiv.org/pdf/1910.11935.pdf

Highly energetic, relativistic electrons are commonly present in many astrophysical systems, from solar flares to the intracluster medium, as indicated by observed electromagnetic radiation. However, open questions remain about the mechanisms responsible for their acceleration, and possible reacceleration. Ubiquitous plasma turbulence is one of the possible universal mechanisms. We study the energization of transrelativistic electrons in turbulence using a hybrid particle-in-cell method, which provides a realistic model of Alfvénic turbulence from MHD to subion scales, and test particle simulations for electrons. We find that, depending on the electron initial energy and turbulence strength, electrons may undergo a fast and efficient phase of energization due to the magnetic curvature drift during the time they are trapped in dynamic magnetic structures. In addition, electrons are accelerated stochastically, which is a slower process that yields lower maximum energies. The combined effect of these two processes determines the overall electron acceleration. With appropriate turbulence parameters, we find that superthermal electrons can be accelerated up to relativistic energies. For example, with heliospheric parameters and a relatively high turbulence level, rapid energization to megaelectronvolt energies is possible
Permanent Link: http://hdl.handle.net/11104/0316197