In this thesis, the current vs. magnetic field relationships for four magnets, M1, M2, M3, and Hyperon of FNAL Experiment E781 (the charm baryon study) havel,een studied on the basis of algorithms involving sign corrections pertaining to remedying incorrect FNAL EPICURE readout system's current and magnetic field values for E78 I's 4 magnets.After analyzing previous BSU personnel's work involving re-averaging of the current and magnetic field output values for E78 1, further research was carried out in this thesis activity regarding the correction of the algebraic signs of certain current and magnetic field values in the FNAL EPICURE read out values inputted into E781' data bank.Firstly, a code was developed to merge the four files of current and magnetic fields for the four magnets of E78 1, all into one file. Then, an algorithm for a sign correction program was developed in order to both sort the merged data and correct the current and magnetic field signautomatically.In order to obtain a better understanding of the effect of the incorrect sign for a magnet's current and magnetic field on analysis results, a statistical result was summarized. Finally, some conclusions were obtained. / Department of Physics and Astronomy

Thesis (Ph.D.) - University of St Andrews, January 2008.

A presente tese parte da premissa de que o contexto de transformações radicais nas Tecnologias da Informação e Comunicação (TICs) desdobra-se em mudanças de toda ordem societal, proporcionando, especialmente, novos modos de subjetivação e cognição a partir da condição habitativa da rede. Tendo isso em vista, examina-se a dissociação entre a cultura tecnocientífica e a cultura das humanidades, ainda presente no modo de produção educacional contemporâneo, a partir das formulações elaboradas por C.P. Snow e Edgar Morin. Discutem-se também alguns parâmetros dos diagnósticos e analisam-se as divergências e pontos comuns nas proposições de ambos os autores. Em um segundo momento, a problemática das “duas culturas” é o pano de fundo de uma reflexão sobre a possibilidade de uma Filosofia da Tecnociência constituir-se em uma estratégia pedagógica relevante para o exercício escolar de religação de saberes, considerando a transversalidade, as hibridações, as tramas multidimensionais e os movimentos transfronteiriços que emergem com os fenômenos tecnocientíficos contemporâneos. Sendo assim, estrategicamente propõe-se a emergência de práticas pedagógicas de matriz filosófica no horizonte transdisciplinar das questões tecnocientíficas. Por fim, entende-se que o atual contexto das tecnologias da conectividade engendra um novo paradigma de inteligibilidade a partir das redes, colaborando para a emergência de um ethos de religação que repercute significativamente no problema das “duas culturas” e na cartografia do saber. / This thesis assumes that the context of radical changes in Information and Communication Technology (ICT) unfolds changes of all societal order, especially providing new forms of subjectivation and cognition from the inhabiting condition in the network. With this in mind, it examines the dissociation between technoscientific culture and the culture of the humanities still present in the contemporary educational production mode, from the formulations developed by C.P. Snow and Edgar Morin. Some parameters of diagnoses are also discussed and the differences and similarities in the propositions of both authors are analyzed. In a second moment, the issue of " the two cultures" is the background for a reflection on the possibility of constituting a Philosophy of Technoscience as a relevant pedagogical strategy for the school exercise of reconnecting knowledge, taking into account the transversality, the hybridizations, the multidimensional plots and transborder movements that emerge with contemporary technoscientific phenomena. Therefore, the emergence of pedagogical practices of philosophical roots in the transdisciplinary horizon of technoscientific issues is strategically proposed. Finally, it is understood that the current context of connectivity technologies engenders a new paradigm of intelligibility from the networks, contributing to the emergence of an ethos of reconnection that significantly affects the issue of two cultures and the cartography of knowledge.

A presente tese parte da premissa de que o contexto de transformações radicais nas Tecnologias da Informação e Comunicação (TICs) desdobra-se em mudanças de toda ordem societal, proporcionando, especialmente, novos modos de subjetivação e cognição a partir da condição habitativa da rede. Tendo isso em vista, examina-se a dissociação entre a cultura tecnocientífica e a cultura das humanidades, ainda presente no modo de produção educacional contemporâneo, a partir das formulações elaboradas por C.P. Snow e Edgar Morin. Discutem-se também alguns parâmetros dos diagnósticos e analisam-se as divergências e pontos comuns nas proposições de ambos os autores. Em um segundo momento, a problemática das “duas culturas” é o pano de fundo de uma reflexão sobre a possibilidade de uma Filosofia da Tecnociência constituir-se em uma estratégia pedagógica relevante para o exercício escolar de religação de saberes, considerando a transversalidade, as hibridações, as tramas multidimensionais e os movimentos transfronteiriços que emergem com os fenômenos tecnocientíficos contemporâneos. Sendo assim, estrategicamente propõe-se a emergência de práticas pedagógicas de matriz filosófica no horizonte transdisciplinar das questões tecnocientíficas. Por fim, entende-se que o atual contexto das tecnologias da conectividade engendra um novo paradigma de inteligibilidade a partir das redes, colaborando para a emergência de um ethos de religação que repercute significativamente no problema das “duas culturas” e na cartografia do saber. / This thesis assumes that the context of radical changes in Information and Communication Technology (ICT) unfolds changes of all societal order, especially providing new forms of subjectivation and cognition from the inhabiting condition in the network. With this in mind, it examines the dissociation between technoscientific culture and the culture of the humanities still present in the contemporary educational production mode, from the formulations developed by C.P. Snow and Edgar Morin. Some parameters of diagnoses are also discussed and the differences and similarities in the propositions of both authors are analyzed. In a second moment, the issue of " the two cultures" is the background for a reflection on the possibility of constituting a Philosophy of Technoscience as a relevant pedagogical strategy for the school exercise of reconnecting knowledge, taking into account the transversality, the hybridizations, the multidimensional plots and transborder movements that emerge with contemporary technoscientific phenomena. Therefore, the emergence of pedagogical practices of philosophical roots in the transdisciplinary horizon of technoscientific issues is strategically proposed. Finally, it is understood that the current context of connectivity technologies engenders a new paradigm of intelligibility from the networks, contributing to the emergence of an ethos of reconnection that significantly affects the issue of two cultures and the cartography of knowledge.

A presente tese parte da premissa de que o contexto de transformações radicais nas Tecnologias da Informação e Comunicação (TICs) desdobra-se em mudanças de toda ordem societal, proporcionando, especialmente, novos modos de subjetivação e cognição a partir da condição habitativa da rede. Tendo isso em vista, examina-se a dissociação entre a cultura tecnocientífica e a cultura das humanidades, ainda presente no modo de produção educacional contemporâneo, a partir das formulações elaboradas por C.P. Snow e Edgar Morin. Discutem-se também alguns parâmetros dos diagnósticos e analisam-se as divergências e pontos comuns nas proposições de ambos os autores. Em um segundo momento, a problemática das “duas culturas” é o pano de fundo de uma reflexão sobre a possibilidade de uma Filosofia da Tecnociência constituir-se em uma estratégia pedagógica relevante para o exercício escolar de religação de saberes, considerando a transversalidade, as hibridações, as tramas multidimensionais e os movimentos transfronteiriços que emergem com os fenômenos tecnocientíficos contemporâneos. Sendo assim, estrategicamente propõe-se a emergência de práticas pedagógicas de matriz filosófica no horizonte transdisciplinar das questões tecnocientíficas. Por fim, entende-se que o atual contexto das tecnologias da conectividade engendra um novo paradigma de inteligibilidade a partir das redes, colaborando para a emergência de um ethos de religação que repercute significativamente no problema das “duas culturas” e na cartografia do saber. / This thesis assumes that the context of radical changes in Information and Communication Technology (ICT) unfolds changes of all societal order, especially providing new forms of subjectivation and cognition from the inhabiting condition in the network. With this in mind, it examines the dissociation between technoscientific culture and the culture of the humanities still present in the contemporary educational production mode, from the formulations developed by C.P. Snow and Edgar Morin. Some parameters of diagnoses are also discussed and the differences and similarities in the propositions of both authors are analyzed. In a second moment, the issue of " the two cultures" is the background for a reflection on the possibility of constituting a Philosophy of Technoscience as a relevant pedagogical strategy for the school exercise of reconnecting knowledge, taking into account the transversality, the hybridizations, the multidimensional plots and transborder movements that emerge with contemporary technoscientific phenomena. Therefore, the emergence of pedagogical practices of philosophical roots in the transdisciplinary horizon of technoscientific issues is strategically proposed. Finally, it is understood that the current context of connectivity technologies engenders a new paradigm of intelligibility from the networks, contributing to the emergence of an ethos of reconnection that significantly affects the issue of two cultures and the cartography of knowledge.

Non-ideal magnetohydrodynamic (MHD) effects may play a significant role in determining the dynamics, thermal properties, and observational signatures of radiatively inefficient accretion flows onto black holes. In particular, particle acceleration during magnetic reconnection events may influence black hole spectra and flaring properties. We use representative general relativistic magnetohydrodynamic (GRMHD) simulations of black hole accretion flows to identify and explore the structures and properties of current sheets as potential sites of magnetic reconnection. In the case of standard and normal evolution (SANE) disks, we find that in the reconnection sites, the plasma beta ranges from 0.1 to 1000, the magnetization ranges from 10(-4) to 1, and the guide fields are weak compared with the reconnecting fields. In magnetically arrested (MAD) disks, we find typical values for plasma beta from 10(-2) to 10(3), magnetizations from 10(-3) to 10, and typically stronger guide fields, with strengths comparable to or greater than the reconnecting fields. These are critical parameters that govern the electron energy distribution resulting from magnetic reconnection and can be used in the context of plasma simulations to provide microphysics inputs to global simulations. We also find that ample magnetic energy is available in the reconnection regions to power the fluence of bright X-ray flares observed from the black hole in the center of the Milky Way.

No description available.

Magnetic reconnection is a fundamental process that changes magnetic field configuration and converts a magnetic energy to flow energy and plasma heating. It can be found in a plasma with frozen magnetic field lines at boundaries where different magnetic field topologies encounter each other and thin current sheets are created as it is typical in the solar wind. In the thesis, we have used spacecraft measurements of solar wind plasma and magnetic field to found magnetic reconnection exhausts. We analyze and compare them with theoretical predictions. The results of the statistical analysis oriented on re-distribution of the magnetic energy in reconnection showed that both a portion of the energy deposited into heat as well as the energy spent on an acceleration of the exhaust plasma increase with the magnetic shear angle in accord with the increase of the magnetic flux available for reconnection. Moreover, we identify unusual events in the solar wind; we found magnetic reconnection exhausts accompanied by one or two side jets and explained their possible causes.

The High Seas, the areas of the ocean beyond national jurisdiction, are experiencing a starkincrease in industrial activities, ranging from fishing to deep sea mining to offshore oil and gasextraction. Marine resources are exploited unsustainably and the benefits of this exploitationare shared unequally. This suggests the need for a transformation, a shift in the deeper structuresof the system, such as underlying paradigms and mind-sets. Engaging with alternative futuresby employing imaginative scenarios can help to question current unsustainable trajectories,uncover alternate possibilities as well as offer aspirational visions of the future. In this thesis, Iargue that depictions of the future that are mere extrapolations of the present do not account fornon-linear changes and surprise, do not explore how current trajectories can be changed andconstrain the capacity to imagine possible futures. Instead, I use a method to address this gapby combining computational text analysis with a structured yet creative scenario buildingapproach. This process results in four science fiction scenario stories, which account for thecomplexity of the system, embrace future uncertainty and engage the imagination, thusdescribing truly novel, transformed futures. The scenario stories are then related back to currentrealities, using the concept of imaginaries, demonstrating that radically futuristic stories can betraced back to the scientific evidence they were based upon. In reference to these results, I arguethat engaging with creative scenario stories can open up transformative spaces to reimagine therelationships between humans and the oceans they depend upon. Further, the scenario storiespresented in this thesis emphasize the vastness of future option space, the plurality of possiblefutures and the subsequent need to continuously explore these uncertain futures from a diversityof perspectives, employing a diversity of methods.

La reconnexion magnétique est un processus fondamental de conversion d'énergie qui se produit dans les plasmas spatiaux ainsi que dans les plasmas de laboratoire. La reconnexion a lieu dans des couches de courant très fines et a comme conséquence la reconfiguration de la topologie magnétique et la conversion d'énergie magnétique dans l'accélération et le réchauffement des particules. Actuellement, le rôle de la reconnexion magnétique est reconnue comme un processus majeur dans l’environnement Soleil-Terre, depuis la couronne solaire jusque dans vent solaire, dans la magnétogaine ainsi qu'à la magnétopause et dans la queue magnétique. La reconnexion se déclenche dans la région de diffusion électronique. Dans cette région, les électrons se démagnétisent et sont accélérés par les champs électriques de reconnexion. Malgré les progrès déterminants dans la compréhension du processus de la reconnexion magnétique qui ont été accomplis grâce à l'utilisation des mesures in-situ en synergie avec les simulations numériques, la physique de la région de diffusion aux échelles électroniques est encore largement inconnue. Ce n'est que dans les dernières années, avec le lancement de la mission Magnetospheric MultiScale (MMS) et l'impressionnant augmentation des capacités de calcul des superordinateurs, que la dynamique de la région de diffusion électronique a commencée à être comprise. Une des questions fondamentales - qui reste encore sans réponse - est de comprendre si la structure de la région de diffusion électronique est homogène ou hétérogène aux échelles électroniques et même au-dessous de ces échelles.La finalité de ma recherche est d’avancer dans la compréhension de la structure de la région de diffusion des électrons avec deux approches diffèrent : les observations par satellites et simulations numériques complètement cinétique de type Vlasov.La première partie de ce mémoire présente les observations issus des satellites MMS en traversant la magnétopause en proximité du point sub-solaire et avec une séparation très petite entre les satellites ($sim 6$ km) i.e. comparable à la longueur d'inertie des électrons $d_e sim 2$ km.L’analyse des donnée montre que la région de diffusion électronique n'est pas homogène en terme de courant électrique et de champ électrique aux échelles électroniques et que la distribution spatiale de la conversion d'énergie est irrégulière aux échelles électroniques. Ces observations indiquent que la structure de la région de diffusion électronique peut être bien plus compliquée que ce qu'indiquent des études expérimentales antérieures et les simulations numériques de type PIC.La présente analyse des données MMS a souligné la nécessité de réaliser des simulations avec une résolution spatiale plus élevée et un bruit numérique négligeable - en particulier pour le champ électrique - pour progresser dans la compréhension des processus cinétiques qui interviennent aux échelles électroniques. En poursuivant cette motivation, la deuxième partie du mémoire est consacrée à l'étude de la région de diffusion électronique en utilisant un nouveaux modèle Eulérien Vlasov-Darwin complètement cinétique qui nous avons implémenté dans le code numérique ViDA. Le code ViDA a été spécifiquement conçu pour perfectionner notre compréhension de la dynamique des plasmas non collisionnels aux échelles cinétiques en donnant accès aux détails de la fonction de distribution électronique dans l’espace de phase. Une première partie est consacrée aux tests du code avec une simulation 2D de la reconnexion magnétique symétrique. Les données de simulation avec bruit négligeable ont été utilisées par la suite pour étudier la contribution des différents termes qui forment la loi d’Ohm dans la région de diffusion électronique. Nous avons traité en particulier la contribution du terme d’inertie électronique qui est responsable de la démagnétisation des électrons. / Magnetic reconnection is a fundamental energy conversion process occurring in space and laboratory plasmas. Reconnection takes place in thin current sheets leading to thereconfiguration of magnetic field topology and to conversion of magnetic energy into acceleration and heating of particles. Today reconnection is recognized to play a key role in the Earth-solar environment, from the solar corona to the solar wind, to magnetosheath, at the Earth's magnetopause, and in the magnetotail. Reconnection is initiated in the Electron Diffusion Region (EDR), where electrons decouple from the magnetic field and are energized by electric fields. Despite the very significant advances that have been made in the understanding of the magnetic reconnection process by means of in-situ measurements (notably provided by the Cluster mission) and by numerical simulations, the small electron scale physics of the dissipation region remains basically unsolved.It is only in the last years, with the launch of the Magnetospheric MultiScale mission (MMS) together with the recent impressive increasing of computational capabilities of supercomputers, that the dynamics of the Electron Diffusion Region has started to be enlightened. One of the key, yet still open questions, is whether the EDR has a preferred homogeneous or inhomogeneous structure at electron scales and below.The purpose of this Thesis is to advance in the understanding of the structure of the Electron Diffusion Region using two different approaches, notably MMS spacecraft observations and kinetic full Vlasov simulations. The first part presents MMS observations of an EDR encounter at the subsolar magnetopause when the four MMS probes were located at the smallest interspacecraft separationof $sim 6 $ km, which is comparable to a few electron inertial length ($d_e sim 2$ km).We find that the EDR is rather inhomogeneous at electron scales in terms of current density and electric field which appear to be different at different spacecraft. In addition, the pattern of the energy conversion is patchy, showing that the structure of the EDR at the magnetopause can be much more complex than it has been found in other MMS events and than it is usually depicted by kinetic PIC simulations.Our MMS data analysis has pointed out the need of simulations with better spatial resolution and low noise on the electron scales, in particular on the electric field, in order to better understand the kinetic physics at play at electron scales. Following this motivation, the second part of the Thesis aims at studying the EDR by using a novel fully-kinetic Eulerian Vlasov-Darwin model which we have implemented in the numerical ViDA code.The ViDA code is specifically designed to improve our understanding of the kinetic dynamics of collisionless plasma at electron scales by giving access to the fine phase space details of the electron distribution function. A first part is devoted to the testing of the code by performing 2D symmetric magnetic reconnection simulations. Then, low-noise simulation data have been used to investigate the contribution of the different terms in the Ohm's law in the EDR, focusing on the contribution of the electron inertia term which is responsible for the decoupling of the electron dynamics from the magnetic field.