E s-q layer at huancayo during the March 1970 geomagnetic storm

Abstract

The paper describes a comparison of vertical electron drift in the F-region ( V z ) measured by VHP incoherent scatter radar at Jicamarca with the corresponding variations of geomagnetic horizontal field ( H) and the maximum frequency reflected from The E s layer ( E s ) at Huancayo during the geomagnetic storm period 7–9 March, 1970. The V z is generally upward during the daytime at the equator, but during 7–9, March, 1970, V z was negative for brief periods associated with negative bays in H. These periods of abnormally low or of downward V z correspond closely with the period of complete disappearance of the q type of E s layer. The magnetic bays associated with the intensification of ring current do not affect the equatorial E s - q and it is only the negative bays in H at the equator due to the ionospheric current flowing westward, that cause sudden disappearance of E s − q. It is suggested that the q type of E s is due to cross-field instability created in the electrojet region due to interaction of northward magnetic field and vertical upward Hall polarization electric field when the plasma density gradient is upward. The sudden disappearances of E s − q are due to the reversal of the horizontal electric field in the equatorial ionosphere and thereby due to the reversal of the equatorial electrojet currents. These reversals of electric field may be due to the imposition on the normal S q field of another westward electric field.