2014/06/18 by Anil Raghav, Ankush Bhaskar, Ajay Lotekar +2 · 1 citation
Physics and Astronomy · #Amplitude #Forbush decrease #Interplanetary spaceflight #Ionosphere and magnetosphere dynamics #Lightning and Electromagnetic Phenomena #Neutron monitor #Rigidity (electromagnetism) #Shock (circulatory) #Shock wave #Solar and Space Plasma Dynamics #Solar wind #astro-ph.SR
paper · pdf · doi:10.1088/1475-7516/2014/10/074
published as Journal of Cosmology and Astroparticle Physics Volume 2014 October 2014 · 24 pages, 11 figures
arxiv created 2014/06/18 · openalex publication_date 2014/10/29 · arxiv updated 2014/12/11 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/05
We have studied the Forbush decrease (FD) event that occurred on February 14, 1978 using 43 neutron monitor observatories to understand the global signature of FD. We have studied rigidity dependence of shock amplitude and total FD amplitude. We have found almost the same power law index for both shock phase amplitude and total FD amplitude. Local time variation of shock phase amplitude and maximum depression time of FD have been investigated which indicate possible effect of shock/CME orientation. We have analyzed rigidity dependence of time constants of two phase recovery. Time constants of slow component of recovery phase show rigidity dependence and imply possible effect of diffusion. Solar wind speed was observed to be well correlated with slow component of FD recovery phase. This indicates solar wind speed as possible driver of recovery phase. To investigate the contribution of interplanetary drivers, shock and CME in FD, we have used shock-only and CME-only models. We have applied these models separately to shock phase and main phase amplitudes respectively. This confirms presently accepted physical scenario that the first step of FD is due to propagating shock barrier and second step is due to flux rope of CME/magnetic cloud.