28 research outputs found
Specific interplanetary conditions for CIR-, Sheath-, and ICME-induced geomagnetic storms obtained by double superposed epoch analysis
The comparison of specific interplanetary conditions for 798 magnetic storms
with Dst < -50 nT for the period 1976-2000 was made on the basis of the OMNI
archive data.We categorized various large-scale types of solar wind as
interplanetary drivers of storms: corotating interaction region (CIR), Sheath,
interplanetary CME (ICME) including magnetic cloud (MC) and Ejecta, separately
MC and Ejecta, and "Indeterminate" type. The data processing was carried out by
the method of double superposed epoch analysis which uses two reference times
(onset of storm and the minimum Dst index) and make a re-scaling of main phase
of storm a such way that after this transformation all storms have equal
durations of main phase in new time reference frame. This method reproduced
some well-known results and allowed us to obtain some new results.
Specifically, obtained results demonstrate high importance of Sheath in
generation of magnetic storms as well as a significant differences in
properties of MC and Ejecta and in their geoeffectiveness.Comment: 21 pages, 9 figures, 1 table, submitted to J. of Advances in Space
Research on 29 July, 2009 for Special Issue "Space Weather Advances