Cross-discipline study of the two-fluid dynamics and energetics of the magnetic reconnection in laboratory and space plasmas

A main goal of the IPELS meeting have been to study the common physics of plasmas through inter-discipline collaborations. Despite huge differences in the physical size of the reconnection layer (by a million), remarkably self-similar characteristics are observed in both laboratory (MRX) and magnetosphere plasmas. In the recent years, the dynamics and physical mechanisms governing the energy conversion have been comparatively studied with data from laboratory and space in the context of two-fluid physics, aided by numerical simulations [1]. In strongly asymmetric reconnection layers with negligible guide field, the energy deposition to electrons is found to primarily occur in the electron diffusion region where electrons are demagnetized and diffuse. A large potential well is observed within the reconnection plane and ions are accelerated by the electric field toward the exhaust region. Furthermore, it was found in MRX and numerical simulation study that a sizable amount (55%) of inflow magnetic energy is converted to ions and electrons in an asymmetric reconnection layer of a few ion skin depths. While this measurement is yet to be verified in the magnetosphere measurement by MMS, future MMS inventory study by multiple MMS crossings would be able to address this key result. Recently, a concept of a super-cluster cubesat system has been proposed, which is based on a 2D (11×11) or 3D (5×5×5) satellite grid with an equal distance in Earth’s magnetosphere [2]. Since the key two-fluid physics occurs in the scale length of 1–200 km, optimal distance between adjacent satellites is 2–50 km, such that the grid size can be 20–500 km. This system can be used for measuring the structure of the magnetic reconnection layer at a given time, directly contributing to understanding the global dynamics of magnetic reconnection in space. It can also provide data of the energy inventory in space, as well as data of the relation between fast fluctuations in the electron diffusion region and the reconnection rate.

1. M. Yamada, L.J. Chen, J. Yoo et al, Nature Comms, 2018, DOI: 10.1038/s41467-018-07680-2 2. M. Yamada, Y. Raitses, J. Simmonds, M. Paluszek, “Proc. COSPAR 2017”, Korea (2017)

*In collaboration with L.-J. Chen, J. Yoo, S. Wang, W. Fox, J. Jara-Almote, H. Ji, W. Daughton, A. Le, J. Burch, B. Giles, M. Hesse, T. Moore, Y. Raitses, J. Simmonds, R. Torbert