“Matreshka” model of multilayered current sheet

Abstract

[1] Current sheets are one of the key elements of the Earth's magnetosphere, determining the magnetic energy storage and release. An analytical self-consistent model of multicomponent thin current sheets, where the plasma consists of ions of both solar wind and ionospheric origin, is presented. The influence of the electron population is taken into account assuming Boltzman-like quasi-equilibrium distribution in the electrostatic field, which can lead to a sharp peak in the electron current density in the center of the current sheet. We include the contribution of non-adiabatic O + ions in our model as one of the terms in the Grad -Shafranov-like system of equations describing the quasi-equilibrium configuration. The contribution of the oxygen ions to the total cross-tail current usually does not exceed 30% for realistic conditions, but current ''wings'' carried by O + ions produce significant broadening of the current profile.Citation: Zelenyi, L. M., H. V.

Formation of current density profile in tilted current sheets

“…Of course, beyond our simple model, similar sources may act on J y and J x , and an initial non-Harris structure of the sheet (e.g. Zelenyi et al, 2006) may also contribute. Summarizing, the approximation of a single normal for the whole crossing may work quite well as a general characteristic, but may be not sufficient to interpret the cross-sheet current density profiles.…”

The scale of the magnetotail reconnecting current sheet in the presence of O+

“…This study did not focus specifically on reconnection events. In Artemyev et al [2008], they used a non-Harris sheet model developed by Zelenyi et al [2006] to fit the current sheet. In this model, a flattened tail in the current profile contributed by O + has been taken into account, and the flattened tail of the current sheet does get widened by O + and reaches the scale of the plasma sheet.…”

Comparison of multi-point measurements of current sheet structure and analytical models

“…In the current model the proportion of trapped to transient plasma is set to 15. Addition of oxygen ions (Zelenyi et al, 2006) increases the sheet scale due to larger Larmor radius of heavier ions. Finally, we introduced two Maxwellian ion populations (the colder and the hotter) to simulate plasma distribution with extended power law energy tail.…”

“…Rich et al (1972) assumed that an anisotropy of the pressure tensor is sufficient to obtain a 1-D plasma equilibrium with B z =0. Several other models considering pressure anisotropy have been proposed, for example, the triply split current model, obtained numerically by Bykov et al (2008), the model by Zelenyi et al (2000Zelenyi et al ( , 2006) (see below), and the model of bifurcated sheet, taking into account population of non-adiabatic particles (Sitnov et al, 2003). The last model has been compared with experimental bifurcated current sheet (Sitnov et al, 2006).…”

“…Therefore for comparison with Cluster observations we have chosen the model of anisotropic current sheet, based on quasiadiabatic ion dynamics in the curved magnetic field (Zelenyi et al, 2000). It has further modifications, taking into account asymmetric plasma sources (Malova et al, 2007), electron currents in a fluid approach (Zelenyi et al, 2004a, b), trapped plasma component (Zelenyi et al, 2002), heavy and light ions (Zelenyi et al, 2006) etc. This model is in a good accordance with the particle-in-cell simulations (Mingalev et al, 2007).…”