Cyclic Variations in the Mean Recurrence Times of Solar Flares in Active Regions

The recurrence times RT (also known as waiting times) of solar flares in active regions in soft X-rays are studied using GOES satellite data from 1998 to 2025. It is shown that the RT distribution is fairly well approximated by a lognormal distribution. Based on grouped samples, changes in three types of average values of log RT distributions over time are studied. From these studies, it can be concluded that the average logarithms of recurrence times, regardless of the method of calculation, show variations similar to variations in sunspot numbers SSN; mean RT values vary between 110 and 280 min.