Dayside ionospheric response to changes in IMF polarity: optical and plasma-flow observations

• Published in: Annales Geophysicae
• Main Authors: S. E. Pryse, A. M. Smith, L. Kersley
• Format: Article in Journal/Newspaper
• Language: English
• Published: Copernicus Publications 2000
• Subjects: Science; Q; Physics; QC1-999; Geophysics. Cosmic physics; QC801-809; Ny-Ålesund; Svalbard; Ny Ålesund
• Online Access: https://doi.org/10.1007/s00585-000-0782-7; https://doaj.org/article/d14349d26bb0401597566cf4e3bb37c2

The response of the dayside ionosphere to changes in polarity of the interplanetary magnetic field was observed by two independent techniques. The signatures were seen in the 630.0 nm red-line emission, measured by a meridian scanning photometer at Ny-Ålesund on Svalbard, and also in the line-of-sight plasma velocities monitored by the Finland CUTLASS SuperDARN radar. A time difference of some 6 to 8 min occurred between the responses of the two techniques, with the flows being first to respond. In the present case study, the longer delay in the optics suggests that ion precipitation controls the auroral emission. Key words: Ionosphere (ionosphere-magnetosphere interactions) · Magnetospheric physics (magnetosphere-ionosphere interactions; polar cap phenomena)