Cristiana Dumitrache

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.

ON THE EVOLUTION OF FILAMENTS

A statistical large-scale study of filaments has revealed the existence of a functional dependence of the length of filaments (the angular distance between the ends of a filament, measured on a great circle on a sphere) on their inclination to lines of solar latitude. A cluster analysis method has been applied to the study of filament evolution and an evolutionary classification of filaments is proposed. The results depend on the differential velocity of filaments. Different types of evolution sequences were obtained, and the evolution of some particular filaments was specially analyzed.

Romanian Contributions to the International Heliophysical Year

We present the Romanian activities within the framework of the International Heliophysical Year. All part of IHY aspects will be approached: history, science, education and outreach. In the history aspect, we emphasize the beginning of solar and artificial satellite researches in Romania. As symmetry over times, after fifty years, the solar group started a new phase in its development and research themes, a fact that constituted itself in a challenge for educational programs and new scientific projects. A very important part of our activity during the International Heliophysical Year was the outreach.

Multiwavelengths study of active region 09778

We have studied the evolution and decay of the active region 09778, as well as the evolution of the filament below it and its possible relation with the active region. Using data from SOHO—LASCO, BBSO, Mauna Loa, we analyzed the evolution of active region in different wavelengths. The AR presented high flare productivity. From MDI magnetograms we extrapolate the magnetic field in order to obtain a 3D configuration and to understand flare occurrence.

The Study of AR09767 and Its Neighborhood

In this paper we analyzed the evolution of the active region AR09767 and other two active regions (AR09771 and AR09780) located in its neighborhood, as well as the evolution of the filament associated with our principal active region. Concomitantly, we studied the principal events of AR09767 such as flares and CME. We extrapolate the 3D coronal magnetic field configuration from the photospheric one in order to understand the magnetic field evolution and reconnections during these erupting events.

Contributions to the Sun‐Heliosphere Studies Using SOHO and Ulysses Data

CMEs are one of the most amazing solar phenomena with deep implications in terrestrial life too. Our project covers the follow up of a CME from the solar source to the interplanetary space, using ESA missions. Our research focuses on active regions evolution and magnetic field extrapolation in 3D to reveal magnetic reconnections responsible for flares and other phenomena. Large scale magnetic reconnections are frequently responsible for the filaments destabilization and CMEs onset. Huge polar prominences or complex filaments appearing near the solar maximum and the period of polarity changes often end in spectacular CMEs. SOHO and ground based multiwavelengths observations gain us understand of these phenomena. Another objective of our research is the link between the solar sources of CMEs and the ICMEs registered by Ulysses. The track back of the ICMEs to the Sun constitutes in a challenge and we tried to make connections between the phenomena registered by SOHO and Ulysses during the solar maximum north...

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.

Fifty Years of Solar Research in Bucharest Observatory

The solar physics researches have started fifty years ago in Romania. In 2006 we celebrate fifty years from the first Observations Solaires — bulletin for solar observations published under the aegis of Romanian Academy. The main directions of research in this filed, approached at the Bucharest Observatory are presented.

A CME‐ICME study using data from SOHO and Ulysses

We analyze the solar source of a CME occurred on 2 March 2002, the follow up of its travel through the interplanetary space and the characteristics of the ICME registered by Ulysses satellite.