Summary: THE 22-YEAR SOLAR MAGNETIC CYCLE.
II. FLARE ACTIVITY
G. MARI, M. D. POPESCU, A. C. DONEA, M. MIERLA
Astronomical Institute of the Romanian Academy
St. Cuitul de Argint 5, RO-75212 Bucharest 28, Romania
Abstract. This paper is part of a larger set concerning the study of the last Hale cycle, a cycle that had an
unexpected behaviour. Here we analyze the occurrence of the solar flares registered in X-ray as well as in
H, with the aim to find an explanation for the activity much lower than predicted of the current 11-year
solar cycle. We conclude that it could be determined by a pulse of flare activity in the descendent phase of
the previous cycle, as well as by its belonging to the secular cycle descendent phase.
Key words: 11-year solar cycle 22-year Hale cycle solar flares.
The manifestation of the 22-year solar periodicity, referred to as the solar magnetic cycle or
Hale cycle (HC), can be observed in the solar magnetic field character at large scale as well as in its
smaller scale character, inside the solar active regions.
It is worth studying this 22-year cycle because of its deep physical meanings and also for the
possible explanations that it could offer for understanding the nature of the solar periodicity
generated by the amplifications and rising of the magnetic field from the tachocline. Moreover, this
22-year periodicity is also found in the terrestrial geomagnetic activity (see Rivin, 1998 and the