Internal structure and spatial dimensions of whistler wave regions in the magnetopause boundary layer

Abstract

Abstract. We use whistler waves observed close to the magnetopause as an instrument to investigate the internal structure of the magnetopause-magnetosheath boundary layer. We find that this region is characterized by tube-like structures with dimensions less than or comparable with an ion inertial length in the direction perpendicular to the ambient magnetic field. The tubes are revealed as they constitute regions where whistler waves are generated and propagate. We believe that the region containing tube-like structures extend several Earth radii along the magnetopause in the boundary layer. Within the presumed wave generating regions we find current structures moving at the whistler wave group velocity in the same direction as the waves.

Waves in high-speed plasmoids in the magnetosheath and at the magnetopause

“…Whistler mode waves have been seen in the magnetosphere near the magnetopause in tube-like structures with small (≈ 150 km) perpendicular dimensions (Stenberg et al, 2007). The whistler mode waves we observe inside the plasmoids appear in short bursts, indicating that they are confined to narrow structure also in this case.…”

“…Such waves have also been observed at the magnetopause . Also whistler mode waves have been observed in this part of space, and such waves have been studied extensively in space and laboratory plasmas; see Stenzel (1999) for a review and Stenberg et al (2007), Tenerani et al (2013), Watt et al (2013), Stenzel et al (2008), or Thuecks et al (2012) for a few examples of more recent work. Waves are of particular interest in plasma physics, as it is through waves that energy is transferred when discrete particle effects are negligible as a result of Debye shielding.…”

Numerical Evidence of Undriven, Fast Reconnection in the Solar-Wind Interaction with Earth’s Magnetosphere: Formation of Electromagnetic Coherent Structures

“…Of special relevance is the first evidence of the presence in the magnetotail of coherent magnetic structures (defined as magnetic islands) with typical dimensions of the order of the ion inertial length [9,10] and their link to the generation of energetic suprathermal electrons [11]. Structures of this kind were also observed in the magnetopause [12,13]. In addition, in Ref.…”

“…This model cannot account for kinetic effects that may play an important role in the solar-wind interaction with the Earth's magnetosphere. Coherent magnetic structures on spatial scales of the order of the ion skin depth were observed by Cluster not only at the flank magnetopause [12,13] but also in the near-tail [9][10][11] and downstream of the bow shock [25,26]. Even smaller length scale structures were indeed observed [13,27].…”

Collisionless Kelvin-Helmholtz instability and vortex-induced reconnection in the external region of the Earth magnetotail

“…Magnetic island type structures embedded in a current sheet in the magnetopause were reported in Refs. [21,22] starting from Cluster data and using a magnetohydrostatic reconstruction technique. In addition, a denser plasma layer was observed on the Earth side of these structures.…”