Volume 453, Number 2, July II 2006
|Page(s)||729 - 736|
|Published online||16 June 2006|
Solar bursts gyrosynchrotron emission from three-dimensional sources
Instituto Nacional de Pesquisas Espaciais – INPE, Av. dos Astronautas, 1758 J. da Granja 515, 12227-010 São José dos Campos SP, Brazil e-mail: firstname.lastname@example.org
2 Centro de Rádio Astronomia e Astrofísica Mackenzie – CRAAM, Rua da Consolação, 896, Ed. Amantino Vassão, 01302 São Paulo SP, Brazil
Accepted: 23 February 2006
Aims.In this study we have analyzed the spectral and spatial characteristics of gyrosynchrotron emission and the polarization of solar bursts in a highly inhomogeneous medium. Our main goal was to investigate the effects of the geometry of the source on the resulting spectrum.
Methods.The SOHO/EIT and TRACE high resolution images revealed structured magnetic configurations in detail over solar active regions. In our method, we represent the magnetic field geometry by three-dimensional structures obtained from magnetic field extrapolation, tomography, or any geometry that resembles the observed structures. The gyrosynchrotron radiation was numerically calculated through a modified version of Ramaty's code.
Results.We calculated the radiation produced by non-thermal electron distributions in this complex environment and solved the radiative transfer equation. The results, presented in brightness distribution maps, polarization maps, and spectra, are discussed. Our numerical results agree with statistical analyses of observed spectra present in the literature. We note a spectral broadening due to the spatial and intensity inhomogeneity of the magnetic field and no center-to-limb variations, which cannot be explained by homogeneous source models. The computed maps revealed a non uniform brightness distribution, with small-scale structures, and different spatial characteristics in each frequency. Also, we found different spectral characteristics at different regions of the emitting source. Polarization maps reveal its high dependence on geometry and on the position of the source on the solar disk.
Key words: Sun: flares / Sun: radio radiation / Sun: activity / Sun: magnetic fields / Sun: particle emission
© ESO, 2006
Current usage metrics show cumulative count of Article Views (full-text article views including HTML views, PDF and ePub downloads, according to the available data) and Abstracts Views on Vision4Press platform.
Data correspond to usage on the plateform after 2015. The current usage metrics is available 48-96 hours after online publication and is updated daily on week days.
Initial download of the metrics may take a while.