Spatial and temporal variations of the high-altitude cusp precipitation

Z. N?me?ek (1) , J. Sim?nek (1) , J. Safránková (1) , L. P?ech (1)

1 UK - Univerzita Karlova [Praha, Česká republika] = Charles University [Prague, Czech Republic]

Structured dispersion patterns of the ion precipitation in low- and mid-altitude cusp regions have been reported by many authors. These patterns are interpreted either as temporal features in terms of the pulsed reconnection model or as spatial changes caused by a combination of the particle velocity with the convection of magnetic field lines. It is generally expected that the spatial dispersion is predominantly observed in lower altitudes where the spacecraft crosses a wide range of geomagnetic coordinates in a short time, whereas the high-altitude spacecraft observes temporal changes because it stays nearly on the same field line for a long time.

We have analyzed one pass of the INTERBALL-1/MAGION-4 satellite pair through the high-altitude cusp and found that both temporal and spatial dispersion effects are important even in the magnetopause vicinity. The analysis of the present event shows a spatial nature of the observed dispersion in the LLBL and in the plasma mantle. We have identified two sources of a mantle precipitation operating simultaneously. Our investigations suggest that besides already reported latitudinal dispersion, the longitudinal dispersion can be observed during intervals of sufficiently high east-west interplanetary magnetic field component.

Domaines: Océan, Atmosphère; Sciences de la Terre

Z. N?me?ek, J. Sim?nek, J. Safránková, L. P?ech. Spatial and temporal variations of the high-altitude cusp precipitation. Annales Geophysicae, 2004, 22 (7), pp.2441-2450. ⟨hal-00318839⟩