@Article{MészárosováKaSaFeCeAn:2008:SoDeTy,
               author = "M{\'e}sz{\'a}rosov{\'a}, Hana and Karlick{\'y}, M. and Sawant, 
                         Hanumant Shankar and Fernandes, F. C. R. and Cecatto, Jos{\'e} 
                         Roberto and Andrade, Maria Concei{\c{c}}{\~a}o de",
          affiliation = "{Astronomical Institute of the Academy of Sciences of the Czech 
                         Republic} and {Astronomical Institute of the Academy of Sciences 
                         of the Czech Republic} and {Instituto Nacional de Pesquisas 
                         Espaciais (INPE)} and {Institute of Research and Development 
                         (IP\&D - UNIVAP)} and {Instituto Nacional de Pesquisas Espaciais 
                         (INPE)} and {Instituto Nacional de Pesquisas Espaciais (INPE)}",
                title = "Solar decimetric type III bursts in semi-closed magnetic field 
                         structures",
              journal = "Astronomy \& Astrophysics",
                 year = "2008",
               volume = "484",
               number = "2",
                pages = "529--536",
                month = "June",
             keywords = "sun, radio radiation, corona, flares.",
             abstract = "Aims. We investigate statistically seventeen groups of solar type 
                         III bursts, observed in the frequency range 950-2500 MHz using the 
                         Brazilian Solar Spectroscope (BSS) during the period 1999-2002. 
                         Methods. Using specially-developed Interactive Data Language (IDL) 
                         software called BSSView, the spectral characteristic properties of 
                         the bursts were investigated. For illustration a semi-closed 
                         magnetic field structure with trapped electron beams was modelled 
                         using the particle-in-cell model. Results. Most of the type III 
                         bursts studied in this paper have starting frequencies in the 
                         range 1100-1400 MHz and their average bandwidth, half-power 
                         duration, and interval between adjacent bursts are 116 59 MHz, 108 
                         41 ms, and 647 643 ms, respectively. The number of bursts with 
                         negative frequency drift, which is on average -914 684 MHz s-1, is 
                         greater than the number with positive frequency drift, which is on 
                         average +807 675 MHz s-1. The type III bursts have power-law 
                         distribution function for their half-power duration , bandwidth 
                         and , and frequency drift . Most of the groups of type III bursts 
                         were also found to exhibit either positive or negative group 
                         frequency drifts of on average +53 38 MHz s-1 and -46 42 MHz s-1, 
                         respectively. The detailed statistical analysis suggests that in 
                         the frequency range studied there are two categories of type III 
                         bursts, the average parameters of which we provide in brackets for 
                         each type: a) numerous narrowband bursts (bandwidth ~100 MHz) with 
                         small frequency drift (~500 MHz s-1) in groups with visible group 
                         drift (~50 MHz s-1) and b) less numerous broader band bursts 
                         (bandwidth 171 MHz) with higher frequency drift (~1800 MHz s-1) in 
                         groups without group drift. The statistics of the parameters of 
                         these drifting groups are presented for the first time. The 
                         drifting groups of type III bursts are interpreted as due to 
                         electron beams trapped in moving plasmoids, which are semi-closed 
                         magnetic field structures.",
                  doi = "10.1051/0004-6361:20077634",
                  url = "http://dx.doi.org/10.1051/0004-6361:20077634",
                 issn = "0004-6361 and 1432-0746",
             language = "en",
           targetfile = "aa7634-07.pdf",
        urlaccessdate = "10 maio 2024"
}