Polar cap influx

• Published in: Annales Geophysicae
• Main Authors: J. MacDougall, P. T. Jayachandran
• Format: Article in Journal/Newspaper
• Language: English
• Published: Copernicus Publications 2005
• Subjects: Science; Q; Physics; QC1-999; Geophysics. Cosmic physics; QC801-809; Cambridge Bay
• Online Access: https://doi.org/10.5194/angeo-23-1755-2005; https://doaj.org/article/b9d6bb5d3c2144629ef6690b5f5ed1d4

This study uses digital ionosonde data from a cusp latitude station (Cambridge Bay, 77° CGM lat.) to study the convection into the polar cap. Days when the IMF magnetic field was relatively steady were used. On many days it was possible to distinguish an interval near noon MLT when the ionosonde data had a different character from that at earlier and later times. Based on our data, and other published measurements, we used the interval 10:00-13:00MLT as the cusp interval and calculated the convection into the polar cap in this interval. The integrated convection accounted for only ~1/3 of the open polar cap flux. If the convection through the prenoon/postnoon regions on either side of the cusp was calculated the remaining 2/3 of the flux could be accounted for. The characteristics of the prenoon/postnoon regions were different from the cusp region, and we attribute this to transient flank merging versus more steady frontside merging for the cusp. Keywords. Ionosphere (Plasma convection) Magnetospheric physics (Polar cap phenomenon)