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IJRSP Vol.39 [2010] >
IJRSP Vol.39(4) [August 2010] >
| Title: | Relationship between Dst(min) magnitudes and characteristics of ICMEs |
| Authors: | Kane, R P |
| Keywords: | Interplanetary disturbance
Magnetic clouds
Ejecta
Shocks
Intense storms
Corotating interaction region (CIR)
Interplanetary coronal mass ejections (ICME)
Dst
Interplanetary magnetic field |
| Issue Date: | Aug-2010 |
| Publisher: | CSIR |
| PACS No.: | 96.50.Bh; 96.50.Uv; 96.60.ph; 94.20.Vv |
| Abstract: | All interplanetary disturbances having shocks and directed towards the
Earth are geoeffective, giving at least a storm sudden commencement (SSC) and
giving Dst depressions [Dst(min)] in a wide range -10 to -500 nT, actual
magnitudes roughly proportional to the magnitudes of negative Bz(min) of
interplanetary magnetic field. During 1965-1996, the ejecta and shock events
not accompanied with magnetic clouds (MCs) had only ~17% intense storms
[Dst(min) ≤-200 nT] but ejecta and shocks accompanied with magnetic clouds
(MCs) had ~40% intense storms. For solar cycle 23, ejecta and shocks without
MCs had only ~3% intense storms; but ejecta and shocks accompanied by MCs had
11% intense storms. Thus, events accompanied with MCs gave larger percentage of
intense storms. Events related to corotating interaction regions (CIRs) led to
only weak and moderate storms [Dst(min): -20 nT to -140 nT]. For cycle 23, the
plots of –Bz(min) vs
–Dst(min) for ejecta and shocks without MCs showed a large scatter for the
ranges Bz(min) -3 to -20 nT vs Dst(min)
-5 to
-170 nT. Thus, analysis in this region would give confusing and uncertain
results. Concentrating on intense events [Dst (min) ≤ -200 nT], the Bz(min) vs Dst(min) plot showed a correlation of
only +0.77±0.12, with considerable scatter in the Dst(min) range -200 to -300
nT [for the same value of Bz(min), Dst(min) would have an uncertainty of about
± 50 nT]. The correlation did not improve when Bz(min) was substituted by the
product BzV, or by cumulative negative Bz from the start to the peak of
negative Bz(min). |
| Page(s): | 177-183 |
| CC License: |  CC Attribution-Noncommercial-No Derivative Works 2.5 India |
| ISSN: | 0975-105X (Online); 0367-8393 (Print) |
| Source: | IJRSP Vol.39(4) [August 2010]
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