Numerical Simulation of Effects of Substorm with Current Wedge under station 
Bunia, Zaire 
 
Klimenko M.V. (1), Klimenko V.V.  (2) 
 
(1) Kaliningrad State Technical University, Kaliningrad, Russia 
2 West Department of IZMIRAN, Kaliningrad, Russia 
 
In the given work the results of numerical calculations of the behavior of the 
different ionospheric parameters during modeling substorm under equatorial 
station Bunia, Zaire (1.5°N, 30.2° E) are presented. Substorm has begun at 18:00 
UT. Calculations are executed on the basis of Global Self-consistent Model of 
the Thermosphere, Ionosphere and Protonosphere, developed in WD IZMIRAN, added 
by the new block of calculation of electric fields in the ionosphere. In the 
calculations we considered the superposition of magnetospheric convection 
electric field (at set of field aligned currents of the first and second zones 
and Substorm Current Wedge (SCW) with taking into account particle 
precipitation) and dynamo field generated by thermospheric winds without 
thermospheric tides. Two variants of the assignment of the SCW according to 
Rostoker and Friedrich, 2005 and Volkov and Namgaladze, 1996 are considered. 
Calculations were carried out for conditions of a spring equinox in a minim 
 um of solar activity. It is shown that during substorm there is a significant 
growth of zonal and meridional components of electric field at station Bunia 
that is explained by the penetration of the electric field of magnetospheric 
convection to the equator. At that there are the essential distinctions in 
temporal course of electric field components depending on a choice of the model 
of Substorm Current Wedge, down to change of a sign of the field. The substorm 
causes the negative disturbances in foF2 ~1.5 MHz. At that the electron 
concentration at height of ~300 km falls on two orders. The growth of ion and 
neutral temperatures on ~40 K at height of ~300 km and electron temperature on 
~70 K at the same height takes place. The concentrations of atomic oxygen, n(O), 
and molecular nitrogen, n(N2), at height of ~300 km increase, however, at that 
the ratio n(O)/n(N2) decreases. There is a strengthening of equatorward 
meridional component of thermospheric wind on ~35 m/s at height of ~300 km. At 
that the zonal component of thermospheric wind at the same height, directed on 
the east, varies poorly. The Total Electron Content under station Bunia also 
decreases during substorm. Vertical profiles of electron concentration experience
the strong stratification of the equatorial F2-layer of the ionosphere during substorm.