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IJRSP Vol.41 [2012] >
IJRSP Vol.41(5) [October 2012] >
| Title: | Cosmic ray Forbush decreases after the giant solar flare of 15 February 2011 |
| Authors: | Kane, R P |
| Keywords: | Forbush decrease
Solar flare
Coronal mass ejection (CME)
Geomagnetic storm
Cosmic ray |
| Issue Date: | Oct-2012 |
| Publisher: | NISCAIR-CSIR, India |
| PACS No.: | 94.20.wq; 96.60.ph; 96.60.qe |
| Abstract: | A very strong X-ray solar flare occurred at about 0200 hrs UT on 15 February
2011. It was associated with a coronal mass ejection (CME) but the CME was not
very strong and its interplanetary CME (ICME) took about 70 h to reach the
Earth. Also, the ICME blob had a moderate, short-lived magnetic field B, so the resulting cosmic ray Forbush
decrease (FD) was weak. The Bz
component was only slightly negative, so the resulting geomagnetic storm
magnitude Dst was negligibly small.
Thus, this giant solar flare had very poor geo-effectiveness indicating that
large flares need not necessarily lead to significant storm effects on Earth,
particularly in the early part of a sunspot cycle when overall solar activity
would be weak.
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| Page(s): | 520-523 |
| CC License: |  CC Attribution-Noncommercial-No Derivative Works 2.5 India |
| ISSN: | 0975-105X (Online); 0367-8393 (Print) |
| Source: | IJRSP Vol.41(5) [October 2012]
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