TY - JOUR

T1 - Magnetospheric currents during sawtooth events

T2 - Event-oriented magnetic field model analysis

AU - Kubyshkina, M.

AU - Pulkkinen, T. I.

AU - Ganushkina, N. Yu

AU - Partamies, N.

PY - 2008/8/1

Y1 - 2008/8/1

N2 - The behavior of inner magnetosphere current systems associated with a sawtooth sequence is examined using empirical magnetic field models during a sawtooth event on 18 April 2002. Three different empirical magnetic field models were developed for the same time period. In each case, the models were fitted using in situ magnetic field observations to minimize the differences between the model and observed field values. The results were compared with those previously obtained for a sawtooth event on 22 October 2001. The main features, namely, strong stretching of both nightside and dusk sector magnetic field prior to the injection, strong currents near geosynchronous distance, and strong dusk-sector magnetic field stretching, were all reproduced by all three models also for the April 2002 event. We conclude that these are repeatable and characteristic features of sawtooth events and discuss how the model details influence the minor differences between the models. Simple drift trajectory calculations are used to show that the models, which reproduce the magnetic field quite well, also accurately represent the energetic proton drift periods at geosynchronous orbit.

AB - The behavior of inner magnetosphere current systems associated with a sawtooth sequence is examined using empirical magnetic field models during a sawtooth event on 18 April 2002. Three different empirical magnetic field models were developed for the same time period. In each case, the models were fitted using in situ magnetic field observations to minimize the differences between the model and observed field values. The results were compared with those previously obtained for a sawtooth event on 22 October 2001. The main features, namely, strong stretching of both nightside and dusk sector magnetic field prior to the injection, strong currents near geosynchronous distance, and strong dusk-sector magnetic field stretching, were all reproduced by all three models also for the April 2002 event. We conclude that these are repeatable and characteristic features of sawtooth events and discuss how the model details influence the minor differences between the models. Simple drift trajectory calculations are used to show that the models, which reproduce the magnetic field quite well, also accurately represent the energetic proton drift periods at geosynchronous orbit.

UR - http://www.scopus.com/inward/record.url?scp=55849118510&partnerID=8YFLogxK

U2 - 10.1029/2007JA012983

DO - 10.1029/2007JA012983

M3 - Article

AN - SCOPUS:55849118510

VL - 113

JO - Journal of Geophysical Research: Biogeosciences

JF - Journal of Geophysical Research: Biogeosciences

SN - 0148-0227

IS - 8

M1 - A08211

ER -