Project realised within National Science Centre (NCN) programme Etiuda of funds for a scholarship and foreign fellowship for PhD students. The 6-month foreign fellowship will be realised at Space Science Laboratory (SSL) at University of California, Berkeley. During the fellowship there is planned cooperation with SSL RHESSI Team and NuSTAR Team researchers. Join analysis will focus on selected solar flares observes at the same time by SphinX, RHESSI and NuSTAR. The next task will be analysis of tiny SXR solar flares observed by SphinX spectrophotometer corelated with CME (Coronal Mass Ejection) phenomena. Preliminary analysis shows that even very weak flares can be correlated with CME. There is planned searching for possible relationships between these solar events.