Oscillations in sunspot umbra, -penumbra and the surrounding photosphere
نویسندگان
چکیده
منابع مشابه
On the complexity of umbra and penumbra
Computing shadow boundaries is a di cult problem in the case of non-point light sources. A point is in the umbra if it does not see any part of any light source; it is in full light if it sees entirely all the light sources; otherwise, it is in the penumbra. While the common boundary of the penumbra and the full light is well understood, less is known about the boundary of the umbra. In this pa...
متن کاملGenerating Shadows with an Umbra and Penumbra
An algorithm for generating shadows with an umbra and penumbra due to distributed light sources is presented. The method used is based on the inclusion of the shadow volumes in the object data processed by a depth-buffer visible surface computation. The standard depth-buffer data structure is modified to allow the handling of shadows with a depth-buffer hidden surface algorithm. The algorithm i...
متن کاملLight Source Object Layered Penumbra Umbra
Shadows serve as e ective cues for a user to recognize spatial relations among objects in 3D space. However simple shadows typically used in 3D interfaces are often insu cient for the purpose, and rendering of shadows with real penumbra are not only too costly for interactive interfaces, but also do not enhance their capabilities as spatial cues. Our proposal, layered penumbra is a new interact...
متن کاملLight Source Object Layered Penumbra Umbra Penumbra - 2 ( dark )
Shadows serve as e ective cues for a user to recognize spatial relations among objects in 3D space. However simple shadows typically used in 3D interfaces are often insu cient for the purpose, and rendering of shadows with real penumbra are not only too costly for interactive interfaces, but also do not enhance their capabilities as spatial cues. Our proposal, layered penumbra is a new interact...
متن کاملThick penumbra in a magnetostatic sunspot model
The conjecture that energy transport in sunspot penumbrae occurs through convection by an interchange of magnetic flux tubes is used in order to construct a magnetostatic model for a deep penumbra which is part of a global sunspot model. The model describes an overall mechanical equilibrium between the three stratifications: of the umbra, the penumbra, and of the solar convection zone, all of t...
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ژورنال
عنوان ژورنال: Symposium - International Astronomical Union
سال: 1988
ISSN: 0074-1809
DOI: 10.1017/s0074180900158036