Hydrological monitoring using cosmic ray neutrons is strongly dependent on heliospheric and geomagnetic conditions. To correct for changes in the heliosphere, the most common approach is to use neutron monitor data. Multiple neutron monitor-based correction methods have been proposed. The derivation, inherent assumptions, and limitations of these methods were examined and a novel method...
Precursors (pre – decreases/pre – increases of the cosmic ray intensity) are observed preceding Forbush decreases. The Cosmic Ray Groups of NKUA and IZMIRAN have studied large Forbush decreases (magnitude > 5%) accompanied by geomagnetic storms (i.e., Dst < -100 nT and 5 ≤ Kp-index ≤ 9) regarding precursors. The threshold value of the equatorial anisotropy one hour before the onset of the...
This study presents a statistical analysis of various properties of all recorded until now Ground Level Enhancement (GLE) events, focusing on their association with solar sources. Specifically, we examine the time difference between the onset of the solar flare and the onset of GLE events as well as the correlation between GLE occurrence and amplitude with the main solar flare...
We have studied the sympathetic flares detected by the GOES satellites during the solar period 1975–2017 (i.e., solar cycles 21–24). We found 2204 sympathetic solar flares out of all 77604. The frequency of the occurrence of sympathetic flares depends on the solar cycle activity. The number of sympathetic solar flares increases with the increase in solar activity and decreases as solar...
