EGU General Assembly 2021
© Author(s) 2021. This work is distributed under
the Creative Commons Attribution 4.0 License.

Thin current sheets of sub-ion scales observed in planetary magnetotails

Elena Grigorenko1, Makar Leonenko1, Lev Zelenyi1, Helmi Malova1,2, and Victor Popov1,3
Elena Grigorenko et al.
  • 1Space Research Institute (IKI), Space Physics, Moscow, Russian Federation (
  • 2Scobeltcyn Institute of Nuclear Physics, Moscow State University, Moscow, Russia
  • 3Higher School of Economics, National University, Moscow, Russia

Current sheets (CSs) play a crucial role in the storage and conversion of magnetic energy in planetary magnetotails. Spacecraft observations in the terrestrial magnetotail reported that the CS thinning and intensification can result in formation of multiscale current structure in which a very thin and intense current layer at the center of the CS is embedded into a thicker sheet. To describe such CSs fully kinetic description taking into account all peculiarities of non-adiabatic particle dynamics is required. Kinetic description brings kinetic scales to the CS models. Ion scales are controlled by thermal ion Larmor radius, while scales of sub-ion embedded CS are controlled by the topology of magnetic field lines until the electron motion is magnetized by a small component of the magnetic field existing in a very center of the CS. MMS observations in the Earth magnetotail as well as MAVEN observations in the Martian magnetotail with high time resolution revealed the formation of similar multiscale structure of the cross-tail CS in spite of very different local plasma characteristics. We revealed that the typical half‐thickness of the embedded Super Thin Current Sheet (STCSs) observed at the center of the CS in the magnetotails of both planets is much less than the gyroradius of thermal protons. The formation of STCS does not depend on ion composition, density and temperature,  but it is controlled by the small value of the normal component of the magnetic field at the neutral plane. Our analysis showed that there is a good agreement between the spatial scaling of multiscale CSs observed in both magnetotails and the scaling predicted by the quasi-adiabatic model of thin anisotropic CS taking into account the coupling between ion and electron currents. Thus, in spite of the significant differences in the CS formation, ion composition, and plasma characteristics in the Earth’s and Martian magnetotails, similar kinetic features are observed in the CS structures in the magnetotails of both planets. This phenomenon can be explained by the universal principles of nature. The CS once has been formed, then it should be self-consistently supported by the internal coupling of the total current carried by particles in the CS and its magnetic configuration, and as soon as the system achieved the quasi-equilibrium state, it “forgets” the mechanisms of its formation, and its following existence is ruled by the general principles of plasma kinetic described by Vlasov–Maxwell equations.

This work is supported by the Russian Science Foundation grant № 20-42-04418

How to cite: Grigorenko, E., Leonenko, M., Zelenyi, L., Malova, H., and Popov, V.: Thin current sheets of sub-ion scales observed in planetary magnetotails, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-10978,, 2021.

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