45 research outputs found
Data of magnetic storms and term-day observations from the Prague-Clementinum observatory (1839-1849)
No full textWe provide in digital form unique data observed at Prague-Clementinum in years 1839-1849. The data were obtained by digitising and processing the original old records published in the yearbooks of this historical observatory. The data contain two categories of high cadence observations of magnetic declination and horizontal intensity. The first of these categories captures 73 magnetic storms with their magnitude being of at least a moderate level. The second category is the dense observations during the days that had been agreed for joint measurements by the observatories organised in the Göttingen Magnetic Union (GMU), these measurements being known as term-day observations. Whereas four terms per year were set by GMU, many observatories agreed to carry out additional observations in the eight remaining months. The term-day observations also continued being performed for several years after the end of the GMU activities in 1841. Data of 120 term-days from January 1840 to December 1849 are published. The observations started at 10 p.m. of Göttingen Mean Time and lasted 24 hours. The interval between observations was 5 minutes (in April, June and July 1842 exceptionally 6 minutes). All time data were transformed into UT, based on the longitude of the Göttingen observatory, which was 9.950°. The time shift is thus 39'48''. The date in the file name of magnetic storm indicates the start day of the event, whereas the date in the term-day file name indicates the second day which involves substantial part of the observations (22 out of 24 hours)
Comparing the Dynamic Global Core Plasma Model (DGCPM) With Ground-Based Plasma Mass Density Observations
No full textThe Dynamic Global Core Plasma Model (DGCPM) is an empirical dynamical model of the plasmasphere which, despite its simple mathematical form, or perhaps because of its simple mathematical form, has enjoyed wide use in the space physics modeling community. In this paper we present some recent observations from the European quasi-Meridional Magnetometer Array (EMMA) and compare these with the DGCPM. The observations suggest more rapid daytime refilling and loss than what is described in the DGCPM. We then modify the DGCPM by changing the values of some of its parameters, leaving the functional form intact. The modified DGCPM agrees much better with the EMMA observations. The modification resulted in an order-of-magnitude faster daytime refilling and nighttime loss. These results are also consistent with previous observations of daytime refilling
Některá témata diferenciání a zobecněné geometrie s aplikacemi ve fyzice.
No full textDifferential geometry plays a prominent role in many areas of modern theoretical physics, ranging from electromagnetism and Yang-Mills to Einstein's general theory of relativity. It became a standard tool to investigate both the local and global properties of classical and quantum physical systems. Generalized geometry, as it emerged from string theory and has been first formulated mathematically by Hitchin and his students, proves to be a valuable tool for further study of quantum field theory and strings. We rigorously introduce all essential concepts of differential geometry, which are then crucial to build a basic framework of the generalized tangent bundle. 1Mathematical Institute of Charles UniversityMatematický ústav UKMatematicko-fyzikální fakultaFaculty of Mathematics and Physic
Courant algebroids and string low energy effective actions
No full textCette thèse est consacrée à l'application des méthodes de la géométrie de Poisson dans le contexte de la théorie des cordes, notamment pour étudier la limite d'énergie basse et les dualités de cette dernière. Les résultats contenus dans la thèse sont les suivants: - Reformulation des notions de tenseur de Ricci et de courbure scalaire généralisées aux algébroïdes de Courant. - Dérivation de ces tenseurs de courbure à partir de la variation d'une action naturelle. - Preuve de la compatibilité de la T-dualité de Poisson-Lie avec les transformations infinitésimales du groupe de renormalisation à une boucle, dans la configuration générale. - Preuve de la compatibilité de la T-dualité de Poisson-Lie avec la partie bosonique des équations d'arrière-plan pour les 5 théories des supercordes. - Découverte des nouvelles classes de solutions d'équations de supergravité modifiées sur des espaces symétriques
The intense magnetic storm of March 1918 as recorded by observatory Ógyalla (present day Hurbanovo)
No full textVyšší struktury v matematické fyzice
No full textVyšší struktury nabízejí přirozený jazyk pro popis teorie kalibračních polí. Tato práce poskytuje pedagogický úvod do nezbytného matematického pozadí, včetně graduované geometrie, teorie kategorií a vyšších struktur. Motivujeme a podrobně popisujeme proces kvantování, konkrétně Faddeev-Popovův trik, formalismus Becchi-Rouet-Stora-Tyutina a Batalin-Vilkovského formalismus. Prostřednictvím tohoto přístupu odhalujeme algebraic- kou strukturu teorií polí, kterou ilustrujeme na příkladech, jako je Chern-Simonsova a Yang-Millsova polní teorie.Higher structures offer a natural framework for the description of gauge field theories. This work provides a pedagogical introduction to the necessary mathematical background, including graded geometry, category theory, and higher structures. We motivate and detail the quantization process, namely the Faddeev-Popov trick, the Becchi-Rouet-Stora- Tyutin formalism, and the Batalin-Vilkovisky formalism. Through this approach, we uncover the algebraic structure of field theories, which we illustrate with examples such as Chern-Simons and Yang-Mills theories.Mathematical Institute of Charles UniversityMatematický ústav UKMatematicko-fyzikální fakultaFaculty of Mathematics and Physic
Higher Structures in Mathematical Physics
No full textHigher structures offer a natural framework for the description of gauge field theories. This work provides a pedagogical introduction to the necessary mathematical background, including graded geometry, category theory, and higher structures. We motivate and detail the quantization process, namely the Faddeev-Popov trick, the Becchi-Rouet-Stora- Tyutin formalism, and the Batalin-Vilkovisky formalism. Through this approach, we uncover the algebraic structure of field theories, which we illustrate with examples such as Chern-Simons and Yang-Mills theories
Exceptional algebroids and type IIA superstrings
No full textWe study exceptional algebroids in the context of warped compactifications of type IIA string theory down to dimensions, with . In contrast to the M-theory and type IIB case, the relevant algebroids are no longer exact, and their locali moduli space is no longer trivial, but has distinct points. This relates to two possible scalar deformations of the IIA theory. The proof of the local classification shows that, in addition to these scalar deformations, one can twist the bracket using a pair of -forms, a -form, a -form, and a -form. Furthermore, we use the analysis to translate the classification of Leibniz parallelisable spaces (corresponding to maximally supersymmetric consistent truncations) into a tractable algebraic problem. We finish with a discussion of the Poisson-Lie U-duality and examples given by tori and spheres in , , and dimensions.18 pages, accepted version, added Conclusions, small change
A sign of the dayside current wedge in geomagnetic observations at Stará Ďala (present-day Hurbanovo) on 16 April 1938
No full textThe recently proposed dayside current wedge likely explains the mechanism behind the well-known Carrington geomagnetic storm on 2 September 1859, as well as an event observed in Europe on 29 October 2003. Both events were swift and intense, had unusually short recovery phases, and the most violent variation of the horizontal intensity within them occurred at mid-latitudes in the morning MLT (magnetic local time) sector. In this paper, we add the third event to the two mentioned above, a short-lasting intense mid-latitude geomagnetic field variation that occurred on 16 April 1938. We present the reconstructed magnetogram with magnetic declination recorded at Stará Ďala on 16 April 1938 and demonstrate that, at around 08:30 of MLT, the Stará Ďala Observatory was likely situated within the central part of the wedge. The time series of horizontal intensity and declination from Western Europe and North America are consistent with our hypothesis that the dayside current wedge played a role in the event of 16 April 1938
