Georgeta Maris

Solar cycle 23 analysis

We analyse the solar cycle (SC) 23 behavior. We also make a comparison with some previous cycles and present a few aspects concerning the forecasts made for SC 23 maximum. As regards the following cycle, in accordance to other early predictions, our empirical method, based on observing the are energy release during the descendant phase of the precedent SC, estimate that the amplitude of SC 24 will be low.

Soft X-ray solar flare cycles

We present a statistical investigation of soft X-ray (SXR) solar flare occurrence over the last three 11-yr solar cycles (SCs 21-23, corresponding to the period 1976-2003). We studied not only the monthly number of flares, but we also used an index that estimate the energy emitted by flares in the SXR 1-8 ˚ and (Qx) that we find it better defines their importance in the solar activity cycle. The medium and high importance SXR flares (M&X class) seem to reflect the cycle importance given by the smoothed monthly Wolf numbers (W). SXR flare indices show a delay regarding the sunspot numbers for SC 21, while for SC 22 and 23 their time distribution is almost coincident with W. The level of energy emitted by SXR flares, quantified through the Qx index, is about the same for SCs 21-23 despite the difference between the W curves in the cycles. We also point out the SXR flare behaviour on the cycles descendant phases, with short but intense increases in their activity, that might give useful information about the activity level of the next cycle.

Outstanding results of Romanian solar physics research in the frame of international cooperation and PhD grants abroad

The valuable results of the Romanian solar physics group in different fields of solar and solar‐terrestrial researches are revised. A new index, Qx, was defined by us in order to give an evaluation of the Soft X‐Ray (SXR) flare energy, similarly to the Q index for Hα flares. Seismic emission from solar flares is distinguished by its origin in plain view above the photosphere, as opposed to convective emission, which is hidden beneath the photosphere. To understand the physics of the acoustic radiation responsible for solar quakes a systematic survey covering a large number of X‐class and some M‐class solar flares observed by SOHO/MDI during 1996 and 2006 has been undertaken. A number of papers present the dynamics of the solar corona in the minimum phase (1996) and during the ascending phase (1998) of the solar cycle, using spectral data of LASCO‐C1/SoHO experiment. In particular, the emergence of the slow solar wind at the above mentioned solar cycle phases was studied. A series of contributions subscrib...