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Start Over Creator Bumba, V.

2. Do sympathetic flares really exist?

Creator:
Bumba, V. and Klvaňa, M.
Format:
bez média and svazek
Type:
model:article and TEXT
Subject:
heliophysics, sympathetic flares, and magnetic situation
Language:
Czech
Description:
Earlier results concerning sympathetic flares and time-correlated rádio bursts are compared with the history and dynamics of development of the magnetic situation in active regions with related flaring. An attempt to present observational evidence of the existence of sympathetic flares is made. We are trying to demonstrate that active regions producing such flares are physically related through common dynamical elements whose magnetic fields display parallel evolution.
Rights:
http://creativecommons.org/publicdomain/mark/1.0/ and policy:public

3. Does the local dynamo act in sunspot groups?

Creator:
Bumba, V.
Format:
bez média and svazek
Type:
model:article and TEXT
Subject:
astronomy, sunspot groups, and local magnetic field topology
Language:
Czech
Description:
We summarize our previous results concerning the local magnetic field formation, showing that its sunspot groups developing to reach higher typec C, D, E etc. continue their magnetic evolution during the period of new magnetic flux addition immediately after the first magnetically bipolar balanced stage. It is probably a magnetohydrodynamical process of magnetic field strenthening oř a new magnetic flux generation. It is dosely related to a specific singularity in the local magnetic field topology at the inner field boundary not far from the centre of the group, where the gulf of one polarity is compressed inbetween the boundary curvature of the field of opposite polarity and where large radial velocities can be observed. This is the region, where new peaks of both the leading and the following polarities in a speciál orthogonal relation of the new to the old tubes of lines of force develop, where the greatest field gradiente are formed. The flare frequencies and their importances correlate well with the degree of complexity of magnetic field topology in this situation. The important role of the photosphere in all these processes is underlined.
Rights:
http://creativecommons.org/publicdomain/mark/1.0/ and policy:public

4. Études météoriques

Creator:
Bumba, V. and Link, F.
Format:
bez média and svazek
Type:
model:article and TEXT
Subject:
astronomical research, meteors, and high atmospehre
Language:
Czech
Description:
Une nouvelle méthode de classement thermique des météores permet de déterminer le type de visibilité et la composition de la plupart des météores faibles (> 1^m) dont on connait les altitudes d'apparition et de disparition. Le traitement statistique des trajectoires météoriques conduit à la détermination de différences entre les météores sporadiques et cométaires ainsi qu' à la détermination approchée du gradient de denstét entre 50 et 150 km d'altitude. and Pokračování a rozšíření práce uveřejněné v tomto časopise [2]. Cílem této práce je výzkum vysoké atmosféry pomocí meteorů a tepelná klasifikace meteorů. Pomocí tepelných konstant meteorů odvozených z laboratních dat je možno užitím Öpikovy theorie meteorů a jejího rozšíření v této práci odhadnouti gradient hustoty ve vysoké atmosféře mezi 50 až 150 km výšky. Ve velké většině lze z výšky zážehů zhasnutí meteoru odvoditi jeho typ a složení, zejména u slabších meteorů, kde nelze fotografovati jejich spektra.
Rights:
http://creativecommons.org/publicdomain/mark/1.0/ and policy:public

5. Flare activity and photoelectric measurements of magnetic and velocity fields

Creator:
Klvaňa, M. and Bumba, V.
Format:
bez média and svazek
Type:
model:article and TEXT
Subject:
solar flares, photoelectric magnetograph, and magnetic and velocity fields
Language:
Czech
Description:
The feasibility of using the new photoelectric magnetograph of the Ondřejov Observatory for measuring fast changes in the magnetic and velocity fields of active regions is considered. Large line-of-sight motions were found in growing and decaying sunspots related with areas of magnetic field boundaries and gradients.
Rights:
http://creativecommons.org/publicdomain/mark/1.0/ and policy:public

6. High flare activity and redistribution of solar global magnetic fields

Creator:
Bumba, V., Hejna, L., and Gesztelyi, L.
Format:
bez média and svazek
Type:
model:article and TEXT
Subject:
heliophysics, solar global magnetic fields, and flares
Language:
Czech
Description:
We demonstrate that both in the global scale and in the scale of large and complex active regions the high flare activity is dosely related to the changes in the whole background magnetic field distribution. We found that the disturbances of the normal course of MALs during the years 1965 -1980 correlated with the maxima of flare activity and the mode of MALs distribution with the mean level of solar flare numbers. We showed that the development of activity during the last two ^submaxima of the 21st cycle of solar activity, especially the formation of the white-light flare region of April 1984, were parts of global processes in the solar atmosphere. They were accompanied by a complete reorganization of the MALs patterns, background field sector structure and restructuralization of coronal holes. In both cases, in the global and in the local scales, we could follow the geophysical consequences of the entire reconstruction of global solar field amplified by the direct influence of many large flares.
Rights:
http://creativecommons.org/publicdomain/mark/1.0/ and policy:public

8. 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