Variations of inner magnetospheric currents during the magnetic storm of May 1998

Authors
Citation
Hf. Chen et Wy. Xu, Variations of inner magnetospheric currents during the magnetic storm of May 1998, CH J GEO-CH, 44(4), 2001, pp. 490-499
Citations number
11
Language
CHINESE
art.tipo
Article
Categorie Soggetti
Earth Sciences
Journal title
CHINESE JOURNAL OF GEOPHYSICS-CHINESE EDITION
ISSN journal
0898-9591 → ACNP
Volume
44
Issue
4
Year of publication
2001
Pages
490 - 499
Database
ISI
SICI code
0898-9591(200107)44:4<490:VOIMCD>2.0.ZU;2-9
Abstract
Transient variations of the geomagnetic field at low latitudes are mainly c aused by the current system such as ionospheric dynamo current (IDC), symme tric ring current (SRC), partial ring current-region II field aligned curre nt-ionospheric current system (PRFI). On the other hand, the region I field aligned current ionospheric current system (FACI) cannot be ignored. In th is paper, we analyze the variations of the current systems during the large storm on May 1-6, 1998. Firstly, the S-q - field caused by IDC is calculat ed by using several station pairs, and removed. Then, the fields of other s ources are separated by fitting data to their field models. Results show th at (1) The storm has two steps, during May1-3, PRFI and FACI were not devel oped significantly, they became strong during the substorms of May 4-5. (2) The variation of SRC is similar to D-st variation during the first step an d delays to D-st in the second step. (3) In the second step, PRFI is develo ped before SRC, and SRC depresses associated with the PRFI and FACI recover y. It gives a clue to understand the formation of the ring current and fiel d-aligned currents and their relationship.