On the classifications of the solar active regions (ARs); Case study for solar cycles 23 and 24

Abstract

The declining phase of solar cycle 23 is an important case of study. Many high energetic solar flares occurred in 2003. The occurrence of high energetic solar X-ray flares (X-type) is related to solar cycle’s phases and the state of the active regions producing them. In some cases, the declining phases may be more active than the maximum phase. A statistical study is performed for solar flares (X-class) occurrence at declining and maximum phases of solar activity. The relationships between the X-class flares, SSN and active regions (ARs) will be investigated. The active region productivity of X-flares is in coherence with the number of days of (β – γ – δ) magnetic field. The active regions energies are consumed in the acceleration of protons and production of X-flares among other things (e.g. CME lifting up). The higher the energy of X-flares the lower the proton flux (pfu @ >10 MeV) and vice versa. Keywords: Solar cycle, Declining phase, X-class flare, Active region