Researchers from Institute of Geology and Geophysics,Chinese Academy of Sciences(IGGCAS), University of Science and Technology of China, and Austrian Academy of Sciences have confirmed that interaction between magnetic flux ropes within the diffusion region of magnetic reconnection play the key role in the dynamics of magnetic reconnection and lead to turbulence. The work will be published online in Nature physics on 7 December.
Magnetic reconnection is a fundamental plasma process, by which magnetic free energy can be released explosively to heat and accelerate plasma. Simultaneously, magnetic topologic structure will be rearranged and matter can be transferred in different regimes. In 1946, Australian scientist Ronald Giovanelli firstly proposed the conception of magnetic reconnection to explain the explosive energy release event in the solar atmosphere, called solar flare. After more than half a century, the research has shown that magnetic reconnection is not only the main reason for solar flare but also can be the reason for a number of other explosive phenomena in nature, such as, color mass emissions (CME), planetary storm and substorm, jets in accretion disk, sawtooth instability in Tokamak etc. However, how magnetic free energy is released and what the dynamic processes are in reconnection are still unclear and there is no extensively accepted theory so far.
In order to reveal the dynamic process in the reconnection diffusion region and energy release mechanisms, the most effective and direct method is to analyze the spacecraft data collected in that region. By the data in the highest time resolution from the Cluster mission obtained in the magnetotail, the researchers from IGGCAS and USTC demonstrated that the reconnection diffusion region is filled with magnetic flux ropes and the coalescence of these flux ropes can heat and accelerate plasma. Geophys. Res. Lett. has reported the finding of thin current layer along the reconnection separatrices by they in 2013 and 2014. Based on this previous work, the magnetic flux ropes was supposed to be created by the breakup of the thin current layers. Furthermore, magnetic reconnection will evolve into turbulence due to the repeated formation and interaction of the flux ropes, as shown in the schematic.
This work is sponsored by National Science Foundation of China (NSFC), the National Basic Research Program of China and Austrian Science Fund (FWF) .
A schematic for reconnection diffusion region (IGG）
School of Earth and Space Sciences，University of Science and Technology of China