Universal scaling of thin current sheets in space plasma

<p>Thin current sheets (TCSs) with thicknesses about ion Larmor radii can play the key role in space; particularly they can store and then explosively release the accumulated free energy. The dynamics of ions moving along quasi-adiabatic trajectories in TCSs is different from one of magnetized electrons following guiding center drift orbits. Due to this property TCSs can be described in a frame of a hybrid approach. The thickness of the super-thin embedded electron sheet remains uncertain because of the scale-free character of magnetized electron motion. We propose a new analytical approach to describe the multilayer TCS and provide the universal expression describing the embedded electron sheet as a function of the cross-sheet transversal coordinate z characterizing TCS. We demonstrated that the unique property of the electron sheet is the nonlinear character of magnetic field profile:  <em>B(z) ~ z <sup>1/3 </sup></em>which conforms excellently with MAVEN observations in the Martian magnetotail. </p><p>This work was supported by the Russian Science Foundation (grant # 20-42-04418).</p><p> </p>

Generation of Vortex Lattices at the Liquid–Gas Interface Using Rotating Surface Waves

In this paper, we demonstrate experimentally that by generating two orthogonal standing waves at the liquid surface, one can control the motion of floating microparticles. The mechanism of the vortex generation is somewhat similar to a classical Stokes drift in linear progression waves. By adjusting the relative phase between the waves, it is possible to generate a vortex lattice, seen as a stationary horizontal flow consisting of counter-rotating vortices. Two orthogonal waves which are phase-shifted by π / 2 create locally rotating waves. Such waves induce nested circular drift orbits of the surface fluid particles. Such a configuration allows for the trapping of particles within a cell of the size about half the wavelength of the standing waves. By changing the relative phase, it is possible to either create or to destroy the vortex crystal. This method creates an opportunity to confine surface particles within cells, or to greatly increase mixing of the surface matter over the wave field surface.

Energetic electron transport in the presence of magnetic perturbations in magnetically confined plasmas

The transport of energetic electrons is sensitive to magnetic perturbations. By using three-dimensional numerical simulation of test particle drift orbits we show that the transport of untrapped electrons through an open region with magnetic perturbations cannot be described by a diffusive process. Based on our test particle simulations, we propose a model that leads to an exponential loss of particles.