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UNIVERSITY OF BUCHAREST
FACULTY OF PHYSICS Guest
2024-11-22 2:17 |
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Conference: Bucharest University Faculty of Physics 2003 Meeting
Section: Atomic and Molecular Physics; Astrophysics
Title:
HIGH-SPEAD PLASMA STREAMS IN THE SOLAR WIND
Authors:
G. MARIS1, O. MARIS 2,3,4
Affiliation:
1Astronomical Institute of the Romanian Academy, Str. Cutitul de Argint 5, RO-75212 Bucharest 28, Romania
E-mail: gmaris@aira.astro.ro
2Institute for Space Sciences, P.O.Box MG-23, RO-76900 Bucharest - Magurele, Romania
E-mail: maris@venus.nipne.ro
3Associate researcher at: Astronomical Institute of the Romanian Academy
Str.Cutitul de Argint 5, Bucharest, P.P. Box 28, RO-75212, Romania
4Associate researcher at: Instituto Nationale di Fisica Nucleare, Sezione di Perugia
Via A. Pascoli, 06123 Perugia, Italy
E-mail: Ovidiu.Maris@pg.infn.it
E-mail
Keywords:
Abstract:
The behavior of the high-speed plasma streams (HSPSs) in the solar wind is investigated during the period of the solar cycles nos. 20 – 22 (1964 – 1996). All the streams were classified as co-rotating and flare-generated streams, using their physical characteristics. The analysis is performed taking into account their frequency of appearance and the following parameters: the durations (in days); the maximum velocities; the velocity gradients; the importance of the streams. The two different types of HSPSs according to their solar origin, the co-rotating and the flare-generated streams, as well as all the HSPS, taken together, were considered during two time units: the Bartels rotation and the year.
The time variation of the HSPS parameters and their occurrence rate shows an 11-years periodicity with some differences between the considered solar cycles (nos. 20, 21 and, 22). The solar cycle no. 21 shows a larger number of flare-generated HSPSs as the even cycles (nos. 20 and 22). The even and odd solar cycles are different in the structure of their maxima, too. The different behavior of the HSPS parameters between even and odd solar cycle could be due to the 22-year solar magnetic cycle.
The HSPS propagation through the interplanetary space is affected by its sectorial magnetic structure: generally, four sectors during the maximum solar activity and two sectors during the minimum activity. This structure is established by the magnetic field of the Sun. The distribution of the two HSPS types as a function of the magnetic sector through which they propagate and also of the 11-year cycle phase is discussed. The differences between the three involved solar cycles (nos. 20, 21 and 22) are analyzed based on their ``strength`` and also on their position in the 22-year magnetic cycle.
The geomagnetic consequences of the HSPS on the different phases of the 11-years solar cycle were also evaluated.
Taking into account our results we consider that the solar HSPS sources can not be only the flares and coronal holes but every energetic event able to produce particle acceleration (coronal mass ejections, filament disappearances).
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