Marilena Mierla

Huge Complex Filament Evolution

A complex filament composed by a main body (a huge polar filament), and a tail (a small filament situated between active regions) was observed between 6 and 14 January 2001. We have analyzed its dynamics. The tail suffered a thermal sudden disappearance and reappeared after two days. A decaying active region plays the role of attractor for the complex filament. A spectacular CME, produced after a helical up‐awarded movement of plasma, movement observed in the coronal loops of the main body of the filament during three days before the CME onset. We have analyzed also the CME shape and movement using SOHO data.

Huge Filament Observed in October 2001

A huge filament was observed at Bucharest Observatory between 3 and 10 October 2001. We analyze this feature using our own observations and those from other observatories.

Analysis of 3D Magnetic Reconnections of Two Active Regions

In this paper we analyze the 3D magnetic field configuration of two neighbor active regions observed in October 2001. These active regions are situated near a huge polar filament which had a complex dynamics. We investigate the connections and influences between these active regions and filament evolution. The AR09640 is a well developed region. In its neighborhood emerged the young AR09644 that produced few flares. Our study reveals the 3D magnetic reconnections in all the area.

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.