Kinetic Alfven Waves Near a Dissipative Layer

The spatial structure of kinetic Alfven waves near a dissipative layer is examined. The type of dispersion for kinetic Alfven waves (KAWs) changes inside the dissipative layer: from cold, when the transverse (across the magnetic shells) wavelength is determined by the electron skin depth in plasma, to warm dispersion, when the wavelength is determined by the ion Larmor radius. The characteristic transverse length of a KAW is complex in the dissipative layer, because it decays strongly when interacting with background plasma electrons. The features of phase shifts between the transverse electromagnetic field components of Alfven oscillations are considered. Phase shift can be used to identify the type of Alfven waves observed by satellites in the vicinity of the dissipative layer. The Alfven wave energy absorption in the dissipative layer can lead to the formation of electron fluxes (with electron energies of 2-5 eV) toward the ionosphere and initiate here the stable auroral red (SAR) arcs. An analytical formula is proposed for determining the density of the electron flux toward the ionosphere and the flux of the energy transferred by them.

Automated summary

This study examines the spatial structure of kinetic Alfven waves near a dissipative layer, exploring the changes in dispersion type and phase shifts in the wave characteristics. The absorption of Alfven wave energy in the dissipative layer can lead to the formation of electron fluxes and stable auroral red arcs. An analytical formula is proposed for determining the density of the electron flux toward the ionosphere and the flux of the energy transferred by them.