Pl. Blelly et al., NUMERICAL MODELING OF INTERMITTENT ION OUTFLOW EVENTS ABOVE EISCAT, Journal of atmospheric and terrestrial physics, 58(1-4), 1996, pp. 273-285
EISCAT observations with the UHF and VHF radars of the dynamics of the
upper ionosphere have revealed the occurrence of intermittent ion out
flows with velocities reaching several hundred m s(-1). It was previou
sly shown that, during such events, the topside downward electron heat
flux, inferred from the analysis of the vertical (field-aligned) stru
cture of the electron temperature profiles, increases drastically up t
o values of about 10 mu W m(-2). The numerical models described in a c
ompanion paper are used here to simulate the effects of energy inputs
driven by the magnetosphere. Three main effects are simulated separate
ly: effects of frictional heating related to E x B drifts, effects due
to topside heat flux perturbations and effects of upward field-aligne
d currents of a few tens of mu A m(-2). It is shown that field-aligned
currents and topside heat flux perturbations produce very similar eff
ects and that combining field-aligned currents with frictional heating
allows us to model the overall characteristics of the perturbations o
f the electron density, of the electron and ion temperatures, and of t
he ion vertical velocity. A good agreement with observations is found.