Decay of the Dst field of geomagnetic disturbance after substorm onset and its implication to storm-substorm relation

Details Decay of the Dst field of geomagnetic disturbance after substorm onset and its implication to storm-substorm relation Decay of the Dst field of geomagnetic disturbance after substorm onset and its implication to storm-substorm relation

Jun 1996

adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=1996angeo..14..608i&link_type=abstract

Annales Geophysicae, vol. 14, Issue 6, pp.608-618

Physics

112

Scientific paper

In order to investigate the causal relationship between magnetic storms and substorms, variations of the mid-latitude geomagnetic indices, ASY (asymmetric part) and SYM (symmetric part), at substorm onsets are examined. Substorm onsets are defined by three different phenomena; (1) a rapid increase in the mid-latitude asymmetric-disturbance indices, ASY-D and ASY-H, with a shape of so-called `mid-latitude positive bay\'; (2) a sharp decrease in the AL index; (3) an onset of Pi2 geomagnetic pulsation. The positive bays are selected using eye inspection and a pattern-matching technique. The 1-min-resolution SYM-H index, which is essentially the same as the hourly Dst index except in terms of the time resolution, does not show any statistically significant development after the onset of substorms; it tends to decay after the onset rather than to develop. It is suggested by a simple model calculation that the decay of the magnetospheric tail current after substorm onset is responsible for the decay of the Dst field. The relation between the IMF southward turning and the development of the Dst field is re-examined. The results support the idea that the geomagnetic storms and substorms are independent processes; that is, the ring-current development is not the result of the frequent occurrence of substorms, but that of enhanced convection caused by the large southward IMF. A substorm is the process of energy dissipation in the magnetosphere, and its contribution to the storm-time ring-current formation seems to be negligible. The decay of the Dst field after a substorm onset is explained by a magnetospheric energy theorem. Acknowledgements. This study is supported in part by the Ministry of Education, Science, Sports, and Culture in Japan, under a Grant-in-Aid for Scientific Research (Category B). Topical Editor D. Alcaydé thanks M. Lockwood and N. J. Fox for their help in evaluating this paper.-> Correspondence to: Y. Kamide->

Affiliated with

Also associated with

No associations

Rating

Decay of the Dst field of geomagnetic disturbance after substorm onset and its implication to storm-substorm relation does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.

If you have personal experience with Decay of the Dst field of geomagnetic disturbance after substorm onset and its implication to storm-substorm relation, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Decay of the Dst field of geomagnetic disturbance after substorm onset and its implication to storm-substorm relation will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-1304618