Self-consistent Seeding of the Interchange Instability in Dipolarization Fronts

Abstract

We report a 3D magnetohydrodynamics simulation that studies the formation of dipolarization fronts during magnetotail reconnection. The crucial new feature uncovered in the present 3D simulation is that the process of reconnection produces flux ropes developing within the reconnection region. These flux ropes are unstable to the kink mode and introduce a spontaneous structure in the dawn-dusk direction. The dipolarization fronts forming downstream of reconnection are strongly affected by the kinking ropes. At the fronts, a density gradient is present with opposite direction to that of the acceleration field and leads to an interchange instability. We present evidence for a causal link where the perturbations of the kinking flux ropes with their natural and well defined scales drive and select the scales for the interchange mode in the dipolarization fronts. The results of the simulation are validated against measured structures observed by the Themis mission.

4 figures, to appear on Geophys. Res. Lett

References in corpus (2)

• Instability of current sheets and formation of plasmoid chains
• Self-Feeding Turbulent Magnetic Reconnection on Macroscopic Scales

Cited by in corpus (8)

• Electromagnetic Energy Conversion in Downstream Fronts from 3D Kinetic Reconnection
• 3D Magnetic Reconnection with a spatially confined X-line extent -- Implications for Dipolarizing Flux Bundles and the Dawn-Dusk Asymmetry
• Local regimes of turbulence in 3D magnetic reconnection
• Non-linear Waves and Instabilities Leading to Secondary Reconnection in Reconnection Outflows
• Are Dipolarization Fronts a Typical Feature of Magnetotail Plasma Jets Fronts?
• Generation of Alfvénic Waves and Turbulence in Reconnection Jets
• Activation of MHD reconnection on ideal timescales
• Where should MMS look for electron diffusion regions?