Astronomy and Astrophysics – Astrophysics
Scientific paper
Feb 2012
adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2012a%26a...538a..28d&link_type=abstract
Astronomy & Astrophysics, Volume 538, id.A28
Astronomy and Astrophysics
Astrophysics
Sun: Coronal Mass Ejections (Cmes), Solar-Terrestrial Relations, Cosmic Rays
Scientific paper
Context. Solar wind disturbances such as interplanetary coronal mass ejections (ICMEs) and corotating interaction regions (CIRs) cause short-term cosmic ray depressions, generally denoted as Forbush decreases. Aims: We conduct a systematic statistical study of various aspects of Forbush decreases. The analysis provides empirical background for physical interpretations of short-term cosmic ray modulations. Methods: Firstly, we analyzed the effects of different types of solar wind disturbances, and secondly, we focused on the phenomenon of over-recovery (the return of the cosmic ray count to a value higher than the pre-decrease level). The analysis is based on ground-based neutron monitor data and the solar wind data recorded by the Advanced Composition Explorer. The correlations between various cosmic ray depressions and solar wind parameters as well as their statistical significance are analyzed in detail. In addition, we performed a normalized superposed epoch analysis for depressions and magnetic field enhancements. Results: The analysis revealed differences in the relationship between different solar wind disturbances and cosmic ray depression parameters. The amplitude of the depression for ICMEs was found to correlate well with the amplitudes of magnetic field strength and fluctuations, whereas for CIRs we found only the correlation between the amplitude of the depression and the solar wind disturbance dimension proxy vtB. Similar behavior was found for shock and no-shock events, respectively. The CIR/ICME composites show a specific behavior that is a mixture of both ICMEs and CIRs. For all analyzed categories we found that the duration of the depression correlates with the duration of the solar wind disturbance. The analysis of the over-recovery showed that there is no straightforward relationship to either "branching-effect" or geomagnetic effects, therefore we propose a scenario where the "branching-effect" is caused by several factors and is only indirectly related to the over-recovery.
Calogovic Jaša
Dumbović M.
Vrsnak Bojan
Župan R.
No associations
LandOfFree
Cosmic ray modulation by different types of solar wind disturbances does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with Cosmic ray modulation by different types of solar wind disturbances, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Cosmic ray modulation by different types of solar wind disturbances will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-887329