Download or read book On the Structure of the Sunspot Zone written by Smithsonian Astrophysical Observatory and published by . This book was released on 1905 with total page 35 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book On the Structure of the Sunspot Zone written by Barbara Bell and published by . This book was released on 2012-03-01 with total page 18 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The Structure of the Sun written by T. Roca Cortes and published by Cambridge University Press. This book was released on 1996-08-28 with total page 422 pages. Available in PDF, EPUB and Kindle. Book excerpt: The complex internal structure of the Sun can now be studied in detail through helioseismology and neutrino astronomy. The VI Canary Islands Winter School of Astrophysics was dedicated to examining these powerful new techniques. Based on this meeting, eight specially-written chapters by world-experts are presented in this timely volume. We are shown how the internal composition and dynamical structure of the Sun can be deduced through helioseismology; and how the central temperature can be determined from the flux of solar neutrinos. This volume provides an excellent introduction for graduate students and an up-to-date overview for researchers working on the Sun, neutrino astronomy and helio- and asteroseismology.
Download or read book The Structure and Development of a Sunspot Group on July 4 8 1966 written by N. V. Steshenko and published by . This book was released on 1970 with total page 22 pages. Available in PDF, EPUB and Kindle. Book excerpt: The structural peculiarities of a group of sunspots during its growth are investigated on the basis of photoheliograms obtained with high resolution. The group is characterized by the complex structure and rapid change in the umbrae of the sunspots. A comparison of the position of filaments of the penumbra with the charts of the transverse magnetic field obtained by A.B. Severnyy and T.T. Tsap shows a generally good agreement in the orientation of the filaments and the field. This is an additional confirmation of the fact that an investigation of the fine structure of spots from direct photographs of the Sun can give supplementary information on the structure and evolution of the strong magnetic field. (Author).
Download or read book The Solar Activity Cycle written by André Balogh and published by Springer. This book was released on 2015-04-16 with total page 594 pages. Available in PDF, EPUB and Kindle. Book excerpt: A collection of papers edited by four experts in the field, this book sets out to describe the way solar activity is manifested in observations of the solar interior, the photosphere, the chromosphere, the corona and the heliosphere. The 11-year solar activity cycle, more generally known as the sunspot cycle, is a fundamental property of the Sun. This phenomenon is the generation and evolution of magnetic fields in the Sun’s convection zone, the photosphere. It is only by the careful enumeration and description of the phenomena and their variations that one can clarify their interdependences. The sunspot cycle has been tracked back about four centuries, and it has been recognized that to make this data set a really useful tool in understanding how the activity cycle works and how it can be predicted, a very careful and detailed effort is needed to generate sunspot numbers. This book deals with this topic, together with several others that present related phenomena that all indicate the physical processes that take place in the Sun and its exterior environment. The reviews in the book also present the latest theoretical and modelling studies that attempt to explain the activity cycle. It remains true, as has been shown in the unexpected characteristics of the first two solar cycles in the 21st century, that predictability remains a serious challenge. Nevertheless, the highly expert and detailed reviews in this book, using the very best solar observations from both ground- and space based telescopes, provide the best possible report on what is known and what is yet to be discovered. Originally published in Space Science Reviews, Vol 186, Issues 1-4, 2014.
Download or read book Sunspots Theory and Observations written by J.H. Thomas and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 422 pages. Available in PDF, EPUB and Kindle. Book excerpt: This volume contains the invited papers presented at the NATO Advanced Research Workshop on the Theory of Sunspots, held in Cambridge, England, 22-27 September 1991. The idea of holding this Workshop first arose during the Solar Optical Telescope work shop on Theoretical Problems in High-Resolution Solar Physics in Munich in 1985. At that meeting, separate discussion groups were formed to consider specific topics in solar physics. The discussion group on sunspots recommended that there be a meeting devoted to theoretical problems associated with sunspots, the motivation being the consensus that theory seemed to lag behind the observational evidence in our quest for a satisfactory un derstanding of the physics of sunspots. This recommendation was warmly received and the two of us were designated to organize the Workshop. Although the Workshop eventually took place later than originally envisioned, the de lay turned out to be fortunate and the timing of the Workshop was ideal for a number of reasons. There have been remarkable improvements in high-resolution observations of sunspots in the past few years, and many important new observational results were pre sented for the first time at this Workshop (by groups working at the Lockheed Palo Alto Research Laboratories, the Swedish and German telescopes in the Canary Islands, and the V. S. National Solar Observatory). Vector magnetographs and Stokes polarimetry have at last given us reliable measurements of the vector magnetic fields in sunspots.
Download or read book On the Structure of Small Sunspots written by Truls Strand Ringnes and published by . This book was released on 1984 with total page 18 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Magnetoconvection written by N. O. Weiss and published by Cambridge University Press. This book was released on 2014-10-30 with total page 411 pages. Available in PDF, EPUB and Kindle. Book excerpt: Leading experts present the current state of knowledge of the subject of magnetoconvection from the viewpoint of applied mathematics.
Download or read book Literature 1978 Part 1 written by S. Böhme and published by Springer Science & Business Media. This book was released on 2013-11-11 with total page 845 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Nuclear Science Abstracts written by and published by . This book was released on 1975-07 with total page 1018 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book New Views of Sunspots written by Jacques Maurice Beckers and published by . This book was released on 1975 with total page 34 pages. Available in PDF, EPUB and Kindle. Book excerpt: The report reviews recent theoretical and observational developments in sunspot physics. It concentrates especially on the recent discoveries of rapid changes in sunspots, most of them oscillatory, and their connection with Alfven waves generated in spots.
Download or read book Structure and Development of Solar Active Regions written by K.O. Kiepenheuer and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 610 pages. Available in PDF, EPUB and Kindle. Book excerpt: K. O. KIEPENHEUER ( Fraunhofer Institut, Freiburg i. Br., Germany) The present symposium, to my knowledge the largest ever held in the field of solar research (170 astronomers from 21 countries) was held in the building of the Hun garian Academy of Sciences in Budapest from September 4 to 8, 1967. It was the 35th symposium organized and sponsored by the International Astronomical Union. The majority of participants were financedfrom national sources. The Organizing Commit tee consisted of K. O. Kiepenheuer (Chairman), L. Davis, L. Dezso (Local Organizer), A.D. Fokker, R. Michard, A.B. Severny, H.J. Smith, Z. Svestka, and H. Tanaka. In order to ensure prompt publication, the manuscripts had to be supplied by the authors 1 month after the meeting. The discussions have been recorded on tape. Their reproduction in this book, however, is based almost completely on the contributors' writing down their comments and questions on the spot. Two special projects have been reported and discussed shortly during the sym posium: The world wide project 'Cooperative Study of Solar Active Regions' (CSSAR) organized by Dr. R. Michard, under the auspices of the IAU, which has put at the disposal of our solar community a precious observing material on Active Regions over a period of 6 months.
Download or read book Turbulence Waves and Instabilities in the Solar Plasma written by R. Erdélyi and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 392 pages. Available in PDF, EPUB and Kindle. Book excerpt: Significant advances have been made recently in both the theoretical understanding and observation of small-scale turbulence in different layers of the Sun, and in the instabilities that give rise to them. The general development of solar physics, however, has led to such a degree of specialization as to hinder interaction between workers in the field. This book therefore presents studies of different layers and regions of the Sun, but from the same aspect, concentrating on the study of small-scale motions. The main emphasis is on the common theoretical roots of these phenomena, but the book also contains an extensive treatment of the observational aspects.
Download or read book On the Decay of Sunspots written by Hanna Strecker and published by . This book was released on 2019 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Abstract: Context: Sunspots are intersections of strong magnetic flux tubes, which penetrate the solar photosphere. They appear as dark patches due to the reduction of convective motions by the strong magnetic field. Observations reveal the fine structure and dynamics of sunspots at the solar surface. The structure of the magnetic flux tube which extends into the solar convection zone remains hidden to real observations. Sunspots can live for days up to several weeks. This is much longer than the dynamical timescale of around an hour. The fanning out of the magnetic field towards the solar surface can stabilise the sunspot due to buoyancy forces. The decay mechanisms and the influence and interaction with the surrounding plasma are part of an ongoing discussion concerning the stability of sunspots. Aims: Mechanisms destabilising a sunspot cannot be observed directly, since they occur below the solar surface. Numerical simulations enable insight into processes below the surface. A study of the structure, evolution and stability of the magnetic flux tube below the surface should lead to insight into the decay mechanism of a sunspot. Methods: We make use of realistic MHD simulations of a sunspot and convective surroundings in a simulation domain which covers an area of 98x98 Mm. The vertical extension of 18 Mm covers approximately 700 km of the solar atmosphere and reaches more than 18 Mm into the convection zone. The analysed data set covers 30 hours. The simulated sunspot and the surrounding regions show characteristics and dynamics which agree with observations. We study the structure and evolution of the magnetic flux tube below the surface. A stability analysis is performed by taking into account the pressure difference between the sunspot and its surroundings, and the inclination of the magnetic field. The connection of moving magnetic features, visible at the solar surface, and their relation to the sunspots evolution is studied. Results and Conclusion: Below the surface, the sunspot is not a simple round flux tube. Perturbations at the boundary of the magnetic flux tube lead to a fluted structure. An interchange instability is responsible for the ragged outer boundary of the sunspot. Field lines are continuously transported from regions of stronger magnetic field to regions of weaker field. The sunspot magnetic flux tube is most unstable at a depth around 3.5 Mm beneath the surface where the raggedness of the sunspot structure is largest. This raggedness increases in time with the indentations becoming deeper. The time evolution shows, that the sunspot structure evolves fastest in between 6 Mm to 10 Mm below the surface with an estimated lifetime of less than 3 days. Towards the surface, the evolution is slower. Buoyancy forces stabilise the sunspot towards the surface, where the magnetic field is more inclined. The continuous transport of field lines at the sunspot boundary leads to a weakening of the magnetic field. Some field lines can detach from the magnetic flux tube. Moving magnetic features which appear at the surface are connected to the regions of interchange. They are tracers of the phenomenon hidden below the surface. In addition, they drag out field lines from the sunspot while they move away from the sunspot. This leads to a magnetic flux loss from the sunspot, which causes its decay within approximately 4 days. Interchange instability leads to a degradation of the sunspot magnetic flux tube below the surface. The stabilisation of the sunspot towards the surface hides this process in observations. In time, the degradation below the surface splits the magnetic flux tube into several smaller ones and eventually destroys the sunspot
Download or read book Plasma Instabilities in Astrophysics written by Donat G. Wentzel and published by CRC Press. This book was released on 1969 with total page 440 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Literature 1988 Part 2 written by Astronomisches Rechen-Institut and published by Springer Science & Business Media. This book was released on 2013-06-29 with total page 1308 pages. Available in PDF, EPUB and Kindle. Book excerpt: From the reviews: "Astronomy and Astrophysics Abstracts has appeared in semi-annual volumes since 1969 and it has already become one of the fundamental publications in the fields of astronomy, astrophysics and neighbouring sciences. It is the most important English-language abstracting journal in the mentioned branches. ...The abstracts are classified under more than a hundred subject categories, thus permitting a quick survey of the whole extended material. The AAA is a valuable and important publication for all students and scientists working in the fields of astronomy and related sciences. As such it represents a necessary ingredient of any astronomical library all over the world." Space Science Reviews#1 "Dividing the whole field plus related subjects into 108 categories, each work is numbered and most are accompanied by brief abstracts. Fairly comprehensive cross-referencing links relevant papers to more than one category, and exhaustive author and subject indices are to be found at the back, making the catalogues easy to use. The series appears to be so complete in its coverage and always less than a year out of date that I shall certainly have to make a little more space on those shelves for future volumes." The Observatory Magazine#2
Download or read book Solar and Stellar Magnetic Activity written by C. J. Schrijver and published by Cambridge University Press. This book was released on 2008-10-30 with total page 404 pages. Available in PDF, EPUB and Kindle. Book excerpt: This timely volume provides the first comprehensive review and synthesis of current understanding of magnetic fields in the Sun and similar stars. Magnetic activity results in a wealth of phenomena - including starspots, non-radiatively heated outer atmospheres, activity cycles, deceleration of rotation rates, and even, in close binaries, stellar cannibalism - all of which are covered clearly and authoritatively. This book brings together for the first time recent results in solar studies and stellar studies. The result is an illuminating new view of stellar magnetic activity. Key topics include radiative transfer, convective simulations, dynamo theory, outer-atmospheric heating, stellar winds and angular momentum loss. Researchers are provided with a state-of-the-art review of this exciting field, and the pedagogical style and introductory material make the book an ideal and welcome introduction for graduate students.
