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2. Bright facular points (filigree) in active regions

Creator:
Zachariadis, Th. G.
Format:
bez média and svazek
Type:
model:article and TEXT
Subject:
solar physics, bright facular points, and observations
Language:
Czech
Description:
High resolution observations of the active region MacMath 16315 near the center of the disk were analysed in order to study the bright points, both below an Arch Filament system and in two neighbouring regions covered by plagettes. The average value of the relative intensity of the bright points with respect to the background in the plagette regions as well as under the Arch Filament system was 1.13 t 0.033. This value was the same for Hα-1.0 A as well as for Hα-0.75 A . The lifetime of bright points under the Arch Filament System ranges from 3 to 18 min with average value of 10 min. The time evolution of the intensity of bright points under the Arch Filament system is different from that of the Ellerman bombs under the same system f. The relative intensity of bright points rises to the maximum value within 1 min and remains constant during the rest of its lifetime. The average size of bright points at Hα-1.0 A was found smaller than that at Hα-0.75 A.
Rights:
http://creativecommons.org/publicdomain/mark/1.0/ and policy:public

3. Fine structure of active regions

Creator:
Muller, R.
Format:
bez média and svazek
Type:
model:article and TEXT
Subject:
solar physics, solar active regions, and photospheric and chromospheric levels
Language:
Czech
Description:
Properties of the line structure of a well developped active region, as visible at the photospheric level, including umbral dots and penumbral filaments of sunspots, facular points, disturbed granules, are described. Properties of a few cbromospheric features are also descoribed because they are dosely connected to tbe pbotospheric ones. Empirical and theoretical models which can explain the observed properties are discussed.
Rights:
http://creativecommons.org/publicdomain/mark/1.0/ and policy:public

4. Fragments in sunspots

Creator:
García de la Rosa, J. I.
Format:
bez média and svazek
Type:
model:article and TEXT
Subject:
solar physics, sunspots, and fragments
Language:
Czech
Description:
High resolution white light and Hα observations carried out at the Observatorio del Teide (Tenerife) witli the 40 cm Vacuum Telescope of the Kiepenheuer Institute (FRG), allow us to study the processes taking place during the development of 15 large active regions (flux larger than 5x1021Mx). The behaviour of the magnetic fragments which coalesce to form the mature spots, inform us about the nature of the subphotospheric flux rope. The following are the main findings; (i) Fragments with typically 1021Mx preserve their identity and even survive to the decay of the sunspots. (ii) Each fragment has a very precise location in the whole ensemble. (iii) The incomplete coalescense of the fragments leaves interstices which are penetrated by hot gas. Tfiis gives a natural explanation of the umbral fine structures (ie. umbral dots and light bridges).
Rights:
http://creativecommons.org/publicdomain/mark/1.0/ and policy:public

5. Magnetic fields of the Sun and stars

Creator:
Bumba, V.
Format:
bez média and svazek
Type:
model:article and TEXT
Subject:
solar physics, solar activities, and magnetic fields
Language:
Czech
Description:
We summarize the main results obtained by the joint effort of solar and stellar physicists in investigating solar and solar type activities in the low-mass main-sequence stars. We demonstrate the basic role of the magnetic field in this activity and the importance of its interaction with the convection and differential rotation of each star. We compile the data obtained by ground-based optical, radio and space ohservations of these stars which provide some idea about the physical conditions in the stellar photospheres, chromospheres and coronae, their activity periodicities and relations of this activity to other stellar parameters. We discuss the possible depth of the dynamo action in the Sun and stars in its relation to the convective zone. We present some results of the method of direct stellar magnetic field measurements in comparison with various indirect evidence of the action of stellar magnetic fields. We also show some observed differences both between the sun- and star-spots, and plages, and we bring information concerning stellar flares. Finally, to compare the main behaviour of magnetic fields on the Sun and stars and the characteristics of the solar and stellar activities, we report some of the new observational results concerning the mutual relation of magnetic and other activities with torsional oscillations, various regularities in latitudinal and longitudinal background field concentration shifts, differential rotation and convection. We also summarize our current knowledge of active region energetics and developments.
Rights:
http://creativecommons.org/publicdomain/mark/1.0/ and policy:public

6. Modelling active region finestructures from observations

Creator:
Wiehr, E.
Format:
bez média and svazek
Type:
model:article and TEXT
Subject:
solar physics, sunspots, and modelling finestructures
Language:
Czech
Description:
Problems, methods and results are discussed to model finestructures of sunspots, plages and prominences from observed data. The very small scales of those structures prevents so far their full resolution in a spectrum. Thus, twocomponent models of other indirect methods are used to deduce model atmosphere, magnetic and velocity field within these finestructures.
Rights:
http://creativecommons.org/publicdomain/mark/1.0/ and policy:public

9. On the long-lived photospheric granules

Creator:
Dialetis, D., Prokakis, Th., Sarris, E., and Tairopoula, G
Format:
bez média and svazek
Type:
model:article and TEXT
Subject:
solar physics, photospheric granules, and long-lived granules
Language:
Czech
Description:
We have studied the spatial distribution of the long-lived granules from a population of 346 granules located in a photospheric region 37"x37". Our study 13 based on an exceptional sequence of photos taken by R. Muller at the Pic-du-Midi Observatory on May 16, 1979. We have determined the lifetime of all the granules situated in this rectangular photospheric region. For the determination of the mean lifetime (15.5 min) we have used a method recently developed (Alissandrakis et aI.. 1987), that permits to define accurately the mean lifetime. Finally we have studied the spatial distribution of the long-lived granules. As long-lived granules we consider all the granules with lifetime greater than the mean lifetime of the population. We found that the long-lived granules are not randomly distributed in the area under study, but they are located in well defined regions with mean length 0"-10" and mean width 2"-4". This result seems to confirm our suggestion (Dialetis et al. 1986) that there are at least two families of granules as for as their lifetime is concerned. We discuss the possible causes of the existence of regions characterized by slower evolutionary process.
Rights:
http://creativecommons.org/publicdomain/mark/1.0/ and policy:public