English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

We present a case study of a prolonged interval of stronglynorthward orientation of the interplanetary magnetic field on 16 July2000, 16:00-19:00 UT to characterize the energy exchangebetween the magnetosphere and ionosphere for conditions associatedwith minimum solar wind-magnetosphere coupling. With reconnectionoccurring tailward of the cusp under northward IMF conditions, thereconnection dynamo should be separated from the viscous dynamo,presumably driven by the Kelvin-Helmholtz (KH) instability. Thus,these conditions are also ideal for evaluating the contribution ofa viscous interaction to the coupling process. We derive thetwo-dimensional distribution of the Poynting vector radialcomponent in the northern sunlit polar ionosphere from magneticfield observations by the constellation of Iridium satellitestogether with drift meter and magnetometer observations from theDefense Meteorological Satellite Program (DMSP) F13 and F15satellites. The electromagnetic energy flux is then compared withthe particle energy flux obtained from auroral images taken by thefar-ultraviolet (FUV) instrument on the Imager for Magnetopause toAurora Global Exploration (IMAGE) spacecraft. The electromagneticenergy input to the ionosphere of 51 GW calculated from theIridium/DMSP observations is eight times larger than the 6 GW dueto particle precipitation all poleward of 78° MLAT. Thisresult indicates that the energy transport is significant,particularly as it is concentrated in a small region near themagnetic pole, even under conditions traditionally considered tobe quiet and is dominated by the electromagnetic flux. We estimatethe contributions of the high and mid-latitude dynamos to both theBirkeland currents and electric potentials finding thathigh-latitude reconnection accounts for 0.8 MA and 45kV while weattribute <0.2MA and ~5kV to an interaction at lowerlatitudes having the sense of a viscous interaction. Given thatthese conditions are ideal for the occurrence of the KHinstability at the magnetopause and hence the viscous interaction,this result suggests that the viscous interaction is a smallcontributor to coupling solar wind energy to themagnetosphere-ionosphere system

High-latitude electromagnetic and particle energy flux during an event with sustained strongly northward IMF