排序方式： 共有5条查询结果，搜索用时 15 毫秒
1
1.
F. Kneer G. Scharmer W. Mattig A. Wyller G. Artzner P. Lemaire J. C. Vial 《Solar physics》1981,69(2):289-300
Observations with the French (L.P.S.P.) experiment on board OSO-8 of a sunspot and nearby plage region are described. The behaviour of the emission cores of the Ca II H and K and Mg II h and k resonance lines is very similar and the correspondence in intensity between the four lines persists in all observed features. In contrast, the Lyman lines show little correlation with the other lines. Their emission regions appear broader in the spectroheliograms than the underlying sunspot structure and must not necessarily possess a counterpart in lower layers. From the central intensity of L above the umbra an electron density of 4.3 × 1010 cm-3 n
e
* 2.3 × 1011 cm-3 at 20 000 K is estimated.Mitteilungen aus dem Kiepenheuer-Institut Nr. 186.Stockholm Observatorium, S-13300 Saltsjöbaden, Sweden.Laboratoire de Physique Stellaire et Planétaire, CNRS, P.O. Box 10, F-91370 Verrières-le-Buisson, France. 相似文献
2.
Blue continuum images of active regions at ∼ 60° from the center of the solar disk obtained with the new Swedish 1-m Solar
Telescope reveal heretofore unreported structure of the magnetized solar atmosphere. Perhaps the most striking aspect of these
images is that, at an angular resolution of 0.12″, they show clearly the three-dimensional structure of the photosphere. In
particular, the Wilson depression of the dark floors of pores is readily apparent. Conversely, the segmented structure of
light bridges running through sunspots and pores reveal that light bridges are raised above the dark surroundings. The geometry
of light bridges permits estimates of the height of their central (slightly darker) ridge: typically in the range 200–450 km.
These images also clearly show that facular brightenings outside of sunspots and pores occur on the disk-center side of those
granules just limbward of intergranular lanes that presumably harbor the associated plage magnetic flux. In many cases the
brightening extends 0.5″ or more over those granules. Furthermore, a very thin, darker lane is often found just centerward
of the facular brightening. We speculate that this feature is the signature of cool down flows that surround flux tubes in
dynamical models. These newly recognized observational aspects of photospheric magnetic fields should provide valuable constraints
for MHD models of the magnetized photosphere, and examination of those models as viewed from oblique angles is encouraged. 相似文献
3.
Henrik Lundstedt Anders Johannesson Göran Scharmer Jan Olof Stenflo Ulf Kusoffsky Birgitta Larsson 《Solar physics》1991,132(2):233-245
A high-resolution videomagnetograph that records the images of opposite circular polarization simultaneously has been constructed for the Swedish vacuum solar telescope at La Palma. Magnetograms are obtained by off-line integration of bursts consisting of typically 50 frames of 20 ms exposures, with bad frames rejected, and the frame-to-frame image motion of the remaining frames compensated for by cross-correlation techniques. The short exposures combined with frame selection and elimination of image motion optimizes the resolution and thereby also the S/N, allowing good magnetograms to be obtained with an effective exposure time of less than 1 s at an image scale of 0.1 pixel–1. The advantages and limitations of the system are discussed and compared with other techniques of making filter magnetograms are discussed. 相似文献
4.
In this paper, we present a time series of Fei 5250.2 Å photospheric filtergrams and corresponding magnetograms in a quiet region. The relationship between fine structures of granulation and magnetic fields is analyzed. It is found that although most bright filigree features in photospheric filtergrams are related to corresponding magnetic features, they are generally not cospatial. It is also found that some bright features and their corresponding photospheric magnetic fields show fast changes within several minutes. 相似文献
5.
We show that the He i 10830 A line gives reliable Doppler shift measurements in the upper chromosphere above active regions. Persistent flow patterns in active regions observed near the solar limb show features previously noted in Dopplergrams using the Civ transition region ultraviolet emission line. Unlike the Civ measurements, however, the He i absorption shows a strong correlation with the line-of-sight velocity images in certain regions of some active regions.Operated by the Association of Universities for Research in Astronomy, Inc., under contract AST 78-17292 with the United States National Science Foundation.The National Center for Atmospheric Research is operated by the University Corporation for Atmospheric Research under sponsorship of the National Science Foundation.Visiting Astronomers, Sacramento Peak Observatory. 相似文献
1