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Regular version of the site

Article

Thin current sheets: from the work of Ginzburg and Syrovatskii to the present day

Physics-Uspekhi. 2016. Vol. 59. No. 11. P. 1057-1090.
Zelenyi L. M., Malova H. V., Grigorenko E. E., V Yu Popov.

 We outline the history and development of the theory of thin current sheets in a collisionless space plasma from the early ideas of V L Ginzburg and S I Syrovatskii to the present day. We review the key achievements of the quasi- adiabatic theory, which provided insight into the fine structure of thin current sheets and enabled a comparison with experi- ment. This comparison showed the quasi-adiabatic approach to be more effective than the classical MHD approximation. With the development of the quasi-adiabatic theory in the last two decades, the existence of a number of new thin current sheet features, such as multi-scaling, metastability, and em- bedding, has been predicted and subsequently confirmed in situ; the role of individual particle populations in the forma- tion of the current sheet fine structure has also been investi- gated. The role of nonadiabatic effects in accelerating plasma beamlets interacting with current sheets is examined. Asym- metry mechanisms in thin current sheets in the presence of a magnetic shear component are described. A study is carried out of current sheet self-organization processes leading to the formation of a shear magnetic component consistent with currents flowing in the plasma. It is demonstrated that the ongoing development of the theory of thin current structures is a logical continuation of Syrovatskii's and Ginzburg's ideas on cosmic rays and reconnected current sheets in the solar corona.