The University of Science and Technology of China reveals new progress in the field of turbulent magnetic field reconnection electron acceleration

Anhui Daily reporter learned from the University of Science and Technology of China on June 13, the school of Earth and space science professor Lu Quanming, Wang Rongsheng research team based on the Earth's magnetosphere multi-scale satellite in-situ detection data, the first time found that the magnetic field reconnected diffusion area can evolve into a turbulent state. The findings were published online June 10 in Nature Communications.

Magnetic field reconnection is a basic plasma physical process. In this process, magnetic free energy is rapidly released and converted into plasma kinetic energy and heat energy, and high-energy electrons are produced. The energetic electrons produced by magnetic reconnection are thought to be the main drivers of phenomena such as gamma-ray bursts, solar flares, and magnetic storms.

Plasma turbulence is another fundamental plasma phenomenon, which exists widely in the space plasma environment. In plasma turbulence, energy can be transported from large to small scales and eventually dissipated at the dynamic scale, heating or accelerating the plasma.

These two basic plasma physical processes are coupled to each other, and turbulence can be generated by reconnection. In turn, the evolution of reconnection is affected by turbulence.

Using satellite data with high spatial and temporal resolution and high precision, the team observed a reconnected current sheet in the Earth's magnetotail current sheet, and the satellite passed through the reconnected diffusion region.

Unlike the typical reconnection model, the diffusion region is not a complete laminar current sheet, but broken into a large number of current filaments. These current filaments of different strength and different scale extend in all directions (mainly in the x and y directions) in the diffusion region, and interweave with each other, forming a three-dimensional mesh current system, that is, the diffusion region is in a turbulent state. In the diffusion region of this turbulent state, the flux of high-energy electrons up to 300 electron volts increases significantly, and the high-energy electrons show a power-law spectral distribution on the distribution function.

The results show that the reconnected diffusion region can evolve into a turbulent state, and the electrons can be effectively accelerated to several hundred electron volts in the turbulent diffusion region.



Anhui Daily Client (2022-06-13)

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