Mapping of the Cosmic Ray Events Related to the Solar Activity for the Period 2003-2005

The relationship between cosmic ray intensity decreases and solar events is still an open field of space research. In this work a complete study of solar events occurred from January 2003 to December 2005, is considered. This three-years time period characterized by an unexpected activity of the Sun was divided into 27-day intervals starting from Bartels Rotation 2313 (06.01.2003) to 2353 (21.12.2005), generating diagrams of the cosmic ray intensity data recorded at the Athens Neutron Monitor Station. This station is working at an altitude of 260m and cut-off rigidity 8.53GV provided to the Internet high-resolution data in real-time. A mapping of all available solar and interplanetary events, such as solar flares with importance M and X, coronal mass ejections (Halo and Partial) was done. As we are going down from the solar maximum to the declining phase of the 23rd solar cycle, a statistical overview of the corresponding relationship among these phenomena, the significant percentage of the connection of Halo CMEs and solar flares and the respective connection to Forbush decreases on yearly and monthly basis are discussed. The close association, as well as a probable quantitative analysis, between solar events is being denoted. The role of extreme solar events occurred in October / November 2003 and January 2005 are also discussed. Obtained results may be useful for predictions of transient solar events and space weather forecasting. • A solar flare (SF) is defined as a sudden, rapid, and intense variation in brightness. It occurs when magnetic energy that has built up in the solar atmosphere is suddenly released. • Coronal Mass Ejections (CMEs) are plasma eruptions from the solar atmosphere involving previously closed regions which are expelled into the interplanetary medium. • Forbush decrease (FD) is a heliospheric phenomenon which is caused in the cosmic rays (CR) by solar wind disturbances, which in their turn – are caused by processes of the Sun In this work a brief presentation of the relation between solar flares (SF), Coronal Mass Ejections (CMEs) and Forbush decreases (FD) recorded at the Athens Neutron Monitor Station for the time period 2003 to 2005 is outlined. This examined period covering forty Bartels Rotations, from BR2313 to BR2353 gives very interesting results on occurred extreme events. Cosmic ray measurements in Athens (37.58 N, 23.47 E) initiated in November 2000 with a standard 6NM-64 neutron monitor. The measurements of the station are being elaborated automatically in order to be compatible to other stations data because of the necessity to compare a number of high rigidity stations in a good quality data which is required for a detailed study of CR variations and space weather conditions. The resolution of the measurements reaches as far as one second – which is uniquely worldwide. Cosmic Ray Intensity from 18:27:30 to 18:30:50 on February 2, 2003