Magnetospheric response to the solar wind as indicated by the cross-polar potential drop and the low-latitude asymmetric disturbance field
2001 (English)In: Annales Geophysicae, ISSN 0992-7689, E-ISSN 1432-0576, Vol. 19, no 6, 649-653 p.Article in journal (Refereed) Published
The cross-polar potential drop Phi (pc), and the low-latitude asymmetric geomagnetic disturbance field, as indicated by the mid-latitude ASY-H magnetic index, are used to study the average magnetospheric response to the solar wind forcing for southward interplanetary magnetic field conditions. The state of the solar wind is monitored by the ACE spacecraft and the ionospheric convection is measured by the double probe electric field instrument on the Astrid-2 satellite. The solar wind-magnetosphere coupling is examined for 77 cases in February and from mid-May to mid-June 1999 by using the interplanetary magnetic field B-z component and the reconnection electric field. Our results show that the maximum correlation between Phi (pc) and the reconnection electric field is obtained approximately 25 min after the solar wind has reached a distance of II R-E from the Earth, which is the assumed average position of the magnetopause. The corresponding correlation for ASY-H shows two separate responses to the reconnection electric field, delayed by about 35 and 65 min, respectively. We suggest that the combination of the occurrence of a large magnetic storm on 18 February 1999 and the enhanced level of geomagnetic activity which peaks at Kp = 7(-) may explain the fast direct response of ASY-H to the solar wind at 35 min, as well as the lack of any clear secondary responses of Phi (pc) to the driving solar wind at time delays longer than 25 min.
Place, publisher, year, edition, pages
2001. Vol. 19, no 6, 649-653 p.
magnetospheric physics, solar wind-magnetosphere interactions, plasma convection, ionosphere, electric fields and currents, north-south component, high time resolution, impulse-response, ionosphere, model, imf, magnetopause, convection, substorm
Fusion, Plasma and Space Physics
IdentifiersURN: urn:nbn:se:kth:diva-20806ISI: 000169921400008OAI: oai:DiVA.org:kth-20806DiVA: diva2:339503
QC 20100525 NR 201408042010-08-102010-08-102012-03-19Bibliographically approved