نتایج جستجو برای: sun photosphere

تعداد نتایج: 35728  

1996
T. E. BERGER

We report on the dynamics of the small-scale solar magnetic field, based on analysis of very high resolution images of the solar photosphere obtained at the Swedish Vacuum Solar Telescope. The data sets are movies from 1 to 4 hr in length, taken in several wavelength bands with a typical time between frames of 20 s. The primary method of tracking small-scale magnetic elements is with very high ...

Akram Gheidi Shahran Taghi Mirtorabi

Distribution of magnetic fields in the quiet-Sun internetwork areas has been affected by weak polarization (in particular Stokes Q and U) signals. To improve the signal-to-noise ratio (SNR) of the weak polarization signals, several approaches, including temporal integrations, have been proposed in the literature. In this study, we aim to investigate a proper temporal-integration time with which...

Journal: :Proceedings of the International Astronomical Union 2006

2007
J. Sánchez Almeida A. Asensio Ramos J. Trujillo Bueno J. Cernicharo

Narrow band imaging in the G-band is commonly used to trace the small magnetic field concentrations of the Sun, although the mechanism that makes them bright has remained unclear. We carry out LTE syntheses of the G-band in an assorted set of semi-empirical model magnetic concentrations. The syntheses include all CH lines as well as the main atomic lines within the band-pass. The model atmosphe...

2009
L. F. Gomes B. V. Gudiksen

We perform a number of numerical simulations of the solar corona with the aim to understand how it responds to different conditions in the photosphere. By changing parameters which govern the motion of the plasma at the photosphere we study the behavior of the corona, in particular, the effects on the current density generated. An MHD code is used to run simulations, using a 20×20×20 Mm box wit...

1998
Noam Soker Geoffrey C. Clayton

We examine the structure of cool magnetic spots in the photospheres of evolved stars, specifically asymptotic giant branch (AGB) stars and R Coronae Borealis (RCB) stars. We find that the photosphere of a cool magnetic spot will be above the surrounding photosphere of AGB stars, opposite to the situation in the sun. This results from the behavior of the opacity, which increases with decreasing ...

2008
M. C. M. Cheung

We present results from numerical modeling of emerging flux regions on the solar surface. The modeling was carried out by means of 3D radiative MHD simulations of the rise of buoyant magnetic flux tubes through the convection zone and into the photosphere. Due to the strong stratification of the convection zone, the rise results in a lateral expansion of the tube into a magnetic sheet, which ac...

1998
MATS G. LO THOMAS E. BERGER RICHARD S. SHINE ALAN M. TITLE

The collection, seeing compensation, and temporal Ðltering of a high-resolution time-sequence of solar photospheric images is described. A 70 minute time series of cospatial and cotemporal G band 4305 Ó and wideband 4686 Ðltergrams was obtained with the 50 cm Swedish Vacuum Solar Telescope on the Ó island of La Palma, Spain. The 29A ] 70A Ðeld-of-view near disk center contains both an enhanced ...

2002
Loukas Vlahos Tassos Fragos Heinz Isliker Manolis Georgoulis

The formation and evolution of active regions are inherently complex phenomena. Magnetic fields generated at the base of the convection zone follow a chaotic evolution before reaching the solar surface. In this article, we use a two-dimensional probabilistic cellular automaton to model the statistical properties of the magnetic patterns formed on the solar surface and to estimate the magnetic e...

2009
Nathan Goldbaum Mark P. Rast Francesco Berrilli

We have measured the average radial (cell center to network boundary) profile of the continuum intensity contrast associated with supergranular flows using data from the Precision Solar Photometric Telescope (PSPT) at the Mauna Loa Solar Observatory (MLSO). After removing the contribution of the network flux elements by the application of masks based on Ca II K intensity and averaging over more...

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