Event calendar file
3-11 July 2007
Merida, Mexico
Mexico/General timezone
- icrc2007@icrc2007.unam.mx
Support
SH.2.1
Solar causes for associated geomagnetic disturbances and cosmic ray decreases
Speakers
- Mr. B.N. MISHRA
Primary authors
- Mr. B.N. MISHRA (A.P.S.University,Rewa (M.P)-486003, INDIA)
Co-authors
- Dr. V.K. MISHRA (A.P.S.University,Rewa (M.P)-486003, INDIA)
- Dr. A.P. MISHRA (A.P.S.University,Rewa (M.P)-486003, INDIA)
Abstract content
Geomagnetic storms (Dst -150nT ≥) and Forbush decrease (Fd magnitude ≥ 5%) in cosmic ray intensity have been selected to study the solar source origin for producing these disturbances. It is found that out of 30 geomagnetic storms, 93% are associated with halo/partial halo coronal mass ejections (CMEs) and 60% with major solar flares whereas, out of 25 FD events, 92% are associated with CMEs and 70% with solar flares. Moreover, it is also found that only 9 observed events (Dst and FDs both) have their common origin due to combined effects of flares and CMEs. The operating mechanism at source and in interplanetary medium will be discussed.
