Thin current sheets caused by plasma flow gradients in space and astrophysical plasma

Abstract

Strong gradients in plasma flows play a major role in space and astrophysical plasmas. A typical situation is that a static plasma equilibrium is surrounded by a plasma flow, which can lead to strong plasma flow gradients at the separatrices between field lines with different magnetic topologies, e.g., planetary magnetospheres, helmet streamers in the solar corona, or at the boundary between the heliosphere and interstellar medium. Within this work we make a first step to understand the influence of these flows towards the occurrence of current sheets in a stationary state situation. We concentrate here on incompressible plasma flows and 2D equilibria, which allow us to find analytic solutions of the stationary magnetohydrodynamics equations (SMHD). First we solve the magnetohydrostatic (MHS) equations with the help of a Grad-Shafranov equation and then we transform these static equilibria into a stationary state with plasma flow. We are in particular interested to study SMHD-equilibria with strong plasma flow gradients perpendicular to separatrices. We find that induced thin current sheets occur naturally in such situations. The strength of the induced currents depend on the Alfvén Mach number and its gradient, and on the magnetic field.

10 pages, 6 figures, published in Annales Geophysicae

References in corpus (4)

• A one-dimensional Vlasov-Maxwell equilibrium for the force-free Harris sheet
• The Breakdown of Alfven's Theorem in Ideal Plasma Flows
• Systematic Construction of Exact 2-D MHD Equilibria with Steady, Compressible Flow in Cartesian Geometry and Uniform Gravity
• Stationary field-aligned MHD flows at astropauses and in astrotails. Principles of a counterflow configuration between a stellar wind and its interstellar medium wind

Cited by in corpus (8)

• Investigation of Dust Ion Acoustic Shock and Solitary Waves in a Viscous Dusty Plasma
• Kinetic equilibrium of two-dimensional force-free current sheets
• Fragmentation of electric currents in the solar corona by plasma flows
• Relation between current sheets and vortex sheets in stationary incompressible MHD
• Self-consistent stationary MHD shear flows in the solar atmosphere as electric field generators
• MHD flows at astropauses and in astrotails
• Electric current filamentation induced by 3D plasma flows in the solar corona
• Stability of the magnetotail current sheet with normal magnetic field and field-aligned plasma flows