Synergy of Stochastic and Systematic Energization of Plasmas during Turbulent Reconnection
Abstract
The important characteristic of turbulent reconnection is that it combines large-scale magnetic disturbances (δ B/B∼ 1) with randomly distributed unstable current sheets (UCSs). Many well-known nonlinear MHD structures (strong turbulence, current sheet(s), shock(s)) lead asymptotically to the state of turbulent reconnection. We analyze in this article, for the first time, the energization of electrons and ions in a large-scale environment that combines large-amplitude disturbances propagating with sub-Alfvénic speed with UCSs. The magnetic disturbances interact stochastically (second-order Fermi) with the charged particles and play a crucial role in the heating of the particles, while the UCSs interact systematically (first-order Fermi) and play a crucial role in the formation of the high-energy tail. The synergy of stochastic and systematic acceleration provided by the mixture of magnetic disturbances and UCSs influences the energetics of the thermal and nonthermal particles, the power-law index, and the length of time the particles remain inside the energy release volume. We show that this synergy can explain the observed very fast and impulsive particle acceleration and the slightly delayed formation of a superhot particle population.
- Publication:
-
The Astrophysical Journal
- Pub Date:
- January 2018
- DOI:
- 10.3847/1538-4357/aaa1e0
- arXiv:
- arXiv:1712.03517
- Bibcode:
- 2018ApJ...852...64P
- Keywords:
-
- acceleration of particles;
- magnetic reconnection;
- methods: numerical;
- Sun: flares;
- turbulence;
- Astrophysics - High Energy Astrophysical Phenomena
- E-Print:
- 6 pages, 3 figures, Accepted for publication in ApJ