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The Successive CME on 13th ; 14th and 15th February 2011 and Forbush decrease on 18 February 2011

Aims. We analyze the kinematics of three interplanetary coronal mass ejections (ICMEs) that occurred on 13th, 14th and 15th February 2011 in the active region AR11155 and have shown that they appeared at the Earth orbit on February, 18th and caused Forbush decrease (FD). Methods. The solar oordinates of flares are (S19W03), (S20W14) and (S21W18). The kinematic curves were obtained using STEREO (A and B) data. Additionally, we explore the possibility of the CME-CME interaction for these three events. We compare obtained estimates of ICME arrival with the in-situ measurements from WIND satellite at L1 point and with ground-based cosmic ray data obtained from SEVAN network.Results. The acceleration of each CME is highly correlated with the associated SXR flares energy release. CMEs that erupted at 13 and 14 Feb 2011 are not associated with rominence eruption ; maximum velocity was vmax= 550 ± 50 km/s and vmax = 400 ± 50 km/s, respectively. However, 15 Feb 2011 CME is connected with much more violent eruption associated with a prominence, with maximum velocity of vmax = 1400 ± 50 km/s. The last overtakes 13th and 14th Feb CMEs at distances of 32 and 160 Rsun, respectively.

mass ejection, solar wind disturbance, pr ominence, flare

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