Micro-scale tearing mode turbulence in the diffusion region during macro-scale evolution of turbulent reconnection
- 1Institute of Physics, University of Graz, Graz, Austria (takuma.tkm.nakamura@gmail.com)
- 2Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency
- 3Space Sciences Laboratory, University of California, Berkeley
- 4Southwest Research Institute
- 5Department of Physics and Astronomy, Dartmouth College
- 6Space Research Institute, Austrian Academy of Sciences
Magnetic reconnection is a key fundamental process in collisionless plasmas that explosively converts magnetic energy to plasma kinetic and thermal energies through a change of magnetic field topology in an electron-scale central region called the electron diffusion region. Past simulations and observations demonstrated that this process causes efficient energy conversion through the formation of multiple macro-scale or micro-scale magnetic islands/flux ropes. However, how these different spatiotemporal scale phenomena are coupled is still poorly understood. In this study, to investigate the turbulent evolution of magnetic reconnection, we perform a new large-scale fully kinetic simulation of a thin current sheet considering a power-law spectrum of initial fluctuations in the magnetic field as frequently observed in the Earth’s magnetotail. The simulation demonstrates that during a macro-scale evolution of turbulent reconnection, the merging of macro-scale islands results in reduction of the rate of reconnection as well as the aspect ratio of the electron diffusion region. This allows the repeated, quick formation of new electron-scale islands within the electron diffusion region, leading to an efficient energy cascade between macro- and micro-scales. The simulation also demonstrates that a strong electron acceleration/heating occurs during the micro-scale island evolution within the EDR. These new findings indicate the importance of non-steady features of the EDR to comprehensively understand the energy conversion and cascade processes in collisionless reconnection.
How to cite: Nakamura, T., Hasegawa, H., Phan, T., Genestreti, K., Denton, R., and Nakamura, R.: Micro-scale tearing mode turbulence in the diffusion region during macro-scale evolution of turbulent reconnection, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-827, https://doi.org/10.5194/egusphere-egu21-827, 2021.