The effect of polar magnetic sub-storms on the equatorial sporadic E
It is known that equatorial sporadic E disappears at night when dynamo field is east to west. During some DP2 type magnetic sub-storms, which cause a depression of the geomagnetic horizontal field at the equator, theq type of sporadic E is found to disappear at the equatorial stations Huancayo and Kodaikanal. This suggests that one of the mechanisms causing the temporary disappearance of Es—q during daytime in equatorial ionograms is the replacement of the east to west dynamo electric field by a west to east electric field due to the imposition of an electric field opposing the normal daytime Sq field.
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