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Apesar dos avanços na última metade de século na teoria de transporte em Física de Plasmas, muitos de seus aspectos ainda são pouco compreendidos. Grande parte dessa limitação se deve à carência de modelos de primeiros princípios minimamente capazes de reproduzir os resultados experimentais. De fato, sem o embasamento em hipóteses fundamentais, os modelos devem se restringir à descrição do comportamento observado nos diferentes regimes de transporte no plasma, sem necessariamente especificar por que ou quais são os mecanismos envolvidos; até mesmo a identificação dos elementos envolvidos no transporte, por exemplo, se partículas ou células convectivas, é prejudicada. Uma abordagem que vem ganhando destaque na comunidade de Física de Plasmas ao longo dos anos é a estatística não-extensiva. Em particular, o interesse na teoria de Tsallis está na sua capacidade de descrever sistemas distantes do equilíbrio termodinâmico, uma característica comum à maioria dos plasmas de laboratório e astrofísicos. De fato, nessas circunstâncias, é sabido que as funções de distribuição das partículas são distantes das distribuições Maxwellianas, com longas-caudas, especialmente para os elétrons. A capacidade da teoria de Tsallis em descrever fenômenos da Física de Plasmas é retratada nas suas diversas aplicações encontradas na literatura, por exemplo, o transporte anômalo, oscilações eletrostáticas, ventos solares, plasmas empoeirados, onde é sabido que as previsões dadas pela estatística de Maxwell-Boltzmann não são capazes de descrever corretamente os resultados experimentais. A proposta desta tese de doutoramento é utilizar a estatística não-extensiva para determinar o transporte colisional em plasmas intensamente magnetizados. O desenvolvimento completo do modelo de transporte no contexto não-extensivo é estabelecido rigorosamente: partindo da definição da entropia de Tsallis e da hipótese das interações fracas (a condição do transporte colisional), somos capazes de deduzir as equações de fluidos utilizando apenas métodos estatísticos genéricos, e sem hipóteses adicionais. Nesse percurso, apresentamos, sempre de maneira consistente com a estatística não-extensiva, a definição da temperatura; a dedução da equação cinética com o operador colisional para plasmas; a generalização do método utilizado por Braginskii para determinar as soluções aproximadas da equação cinética; e o cálculo dos coeficientes de transporte. Porém, também apresentamos a aplicação de nosso modelo no transporte de calor em ventos solares e no pulso frio em plasmas de laboratório. / Despite the advances in the last half century in the plasma transport theory, many aspects of such phenomena remain poorly understood. Most of this limitation is due to the lack o first principles models capable of reproducing experimental observations. In fact, without a fundamental hypothesis, the models are restricted to describing the behavior of the observed plasma transport in diferent regimes, without specifying why or which mechanisms take part in the process; even the determination of the elements involved in the transport, for instance, whether particles or convective cells, is impaired. One approach that has been attracting attention in Plasma Physics community over the years is the non-extensive statistics. In particular, the interest in the Tsallis\'s theory lies in its ability to describe systems far from thermodynamic equilibrium, a common feature in most laboratory and astrophysical plasmas. The capability of the non-extensive statistics in describing phenomena of Plasma Physics is portrayed in various applications, for example, the anomalous transport, electrostatic oscillations, solar winds, dusty plasmas, where it is know that the predictions given by Maxwell-Boltzmann statistics cannot describe the experimental results. Indeed, under such cases, it is well known that the particle distribution functions are quite distant from Maxwellian distributions, with long tails, especially for electrons. The purpose of this doctoral thesis is to use the non-extensive statistics in order to obtain a model for the collisional transport in strongly magnetized plasmas. The complete development of the model in the non-extensive context is strictly established; starting with the definition of the Tsallis entropy and the weak interactions hypothesis (the collisional transport condition), we are able to derive the fluid equations using only generic statistical methods, without additional hypotheses. For such task, we present, consistently with non-extensive statistics, the definition of temperature; the deduction of the kinetic equation with the collision operator for plasmas, which are also appropriated for the determination of the fluid equations; the generalization of the method used by Braginskii to approximate the solution of the kinetic equation for electrons; and the calculation of electron transport coeficients. Lastly, we present the application of our model in the heat transport in the solar winds and in the phenomena of the cold pulse in laboratory plasmas.

Parmi les différents plasmas spatiaux, le vent solaire et les magnétogaines planétaires représentent les meilleurs laboratoires pour l’étude des propriétés de la turbulence. Les fluctuations de densité dans le vent solaire étant faibles, à basses fréquences ces dernières sont généralement décrites par la théorie de la MHD incompressible. Malgré son incompressibilité, l’effet de la compressibilité dans le vent solaire a fait l’objet de nombreux travaux depuis des décennies, à la fois théoriques,numériques et observationnels.Le but de ma thèse est d’étudier le rôle de la compressibilité dans les magnétogaines planétaires(de la Terre et de Saturne) en comparaison avec un milieu beaucoup plus étudié et moins compressible (quasi incompressible), le vent solaire. Ce travail a été réalisé en utilisant des données in-situ de trois sondes spatiales, Cassini, Cluster et THEMIS B/ARTEMIS P1.La première partie de mon travail a été consacrée à l’étude des propriétés de la turbulence dans la magnétogaine de Saturne aux échelles MHD et sub-ionique, en comparaison avec celle de la Terre en utilisant les données Cassini et Cluster respectivement. Ensuite j’ai appliqué la loiexacte de la turbulence isotherme et compressible dans le vent rapide et lent en utilisant les données THEMIS B/ARTEMIS P1, afin d’étudier l’effet et le rôle de la compressibilité sur le taux de transfert de l’énergie dans la zone inertielle. Enfin, une première application de ce modèle dans la magnétogaine de la Terre est présentée en utilisant les données Cluster. / Among the different astrophysical plasmas, the solar wind and the planetary magnetosheathsrepresent the best laboratories for studying the properties of fully developed plasma turbulence.Because of the relatively weak density fluctuations (∼ 10%) in the solar wind, the low frequencyfluctuations are usually described using the incompressible MHD theory. Nevertheless, the effectof the compressibility (in particular in the fast wind) has been a subject of active research withinthe space physics community over the last three decades.My thesis is essentially dedicated to the study of compressible turbulence in different plasma environments,the planetary magnetosheaths (of Saturn and Earth) and the fast and slow solar wind.This was done using in-situ spacecraft data from the Cassini, Cluster and THEMIS/ARTEMISsatellites.I first investigated the properties of MHD and kinetic scale turbulence in the magnetosheathof Saturn using Cassini data at the MHD scales and compared them to known features of thesolar wind turbulence. This work was completed with a more detailed analysis performed in themagnetosheath of Earth using the Cluster data. Then, by applying the recently derived exactlaw of compressible isothermal MHD turbulence to the in-situ observations from THEMIS andCLUSTER spacecrafts, a detailed study regarding the effect of the compressibility on the energycascade (dissipation) rate in the fast and the slow wind is presented. Several new empirical lawsare obtained, which include the power-law scaling of the energy cascade rate as function of theturbulent Mach number. Eventually, an application of this exact model to a more compressiblemedium, the magnetosheath of Earth, using the Cluster data provides the first estimation of theenergy dissipation rate in the magnetosheath, which is found to be up to two orders of magnitudehigher than that observed in the solar wind.

Ma thèse a pour but de comprendre le rôle de la compressibilité dans la turbulence aux basses fréquences dans les plasmas spatiaux (le vent solaire, les plasmas magnétosphériques etc.) et astrophysiques (nuage moléculaire interstellaire, le cœur d'une étoile etc.). Trois nouvelles relations exactes ont été déduites dans le cadre de la turbulence compressible dans un fluide isotherme et polytrope et dans un plasma MHD isotherme afin de comprendre différentes propriétés universelles de la turbulence compressible. De plausibles phénoménologies ont été proposées aussi en vue d'une compréhension de différentes lois de spectre obtenues grâce aux simulations numériques de la turbulence compressible. Une distinction qualitative entre la turbulence sous-sonique et supersonique est ainsi décrite.Une analyse utilisant des données d'observation des sondes spatiales THEMIS est également réalisée dans le but d'expliquer l'effet de la compressibilité dans la turbulence du vent solaire rapide. Une amélioration remarquable par rapport a "incompressible scaling" est observée avec la nouvelle "compressible scaling". Le flux d'énergie correspondant ainsi trouve est estime suffisant pour expliquer le chauffage anormal du vent solaire rapide. / My thesis work is principally dedicated in understanding the role of compressibility in lowfrequency turbulence of space plasmas (the solar wind, magnetospheric plasma etc.) and astrophysical plasmas (interstellar molecular cloud, the core of a star etc.). Three new exact relations have been derived analytically in the framework of isothermal and polytropic hydrodynamic turbulence and also for an isothermal MHD plasma. By using these relations, various universal scalingproperties of compressible turbulence have been investigated. In addition, plausible phenomenologieshave been proposed in order to theoretically reproduce different power laws for energy power spectra which had been obtained in previous numerical simulations of compressible turbulence. A semi-qualitativedistinction between sub-sonic and supersonic regime of turbulence is hence concluded. In the second part, an analysis using THEMIS spacecraft data is also performed in a view to explainingthe effect of the compressibility in the turbulence of the fast solar wind. A remarkable smooth scalingin comparison with incompressible law is obtained for several intervals of fast solar wind. The corresponding turbulent energy flux is also found to be sufficient to explain the anomalous heating of fast solar wind.

This master thesis discuss about ionizing radiation, interaction with matter and effects on her. In the work is discussed differend types of interactions of directly ionizing radiation and indirectly ionizing radiation. Below is an overview of methods of shielding from all of types of ionizing radiation. Second part of this thesis discuss about single event effects in semiconductors which are cause by ionizing radiation. At the end is described design of measuring instrument included FPGA chips. This design is discused both from point of wiew hardware and software too.

This master thesis discuss about ionizing radiation, interaction with matter and effects on her. In the work is discussed differend types of interactions of directly ionizing radiation and indirectly ionizing radiation. Below is an overview of methods of shielding from all of types of ionizing radiation. Second part of this thesis discuss about single event effects in semiconductors which are cause by ionizing radiation. At the end is described design of measuring instrument included FPGA chips. This design is discused both from point of wiew hardware and software too.

Title: Solar Wind Modification in the Earth Foreshock Author: Jaroslav Urbář Department: Department of Surface and Plasma Science Supervisor: Prof. Zdeněk Němeček, Department of Surface and Plasma Science Abstract: The thesis presents statistical studies of the solar wind deceleration and deflection in the foreshock and its potential causes. The multi-point observa- tions from the THEMIS mission in the foreshock are compared with a Wind solar wind monitor with motivation to estimate different factors influencing evolution of solar wind speed and its deflection. We have found a systematic deceleration of the solar wind mainly due to its proton component with a decreasing distance to the bow shock that is controlled by the compressibility and the level of magnetic field fluctuations in the ULF wave range associated with the flux of reflected and accelerated particles. We can conclude that the reflected particles excite waves of large amplitudes that decelerate the solar wind protons throughout the foreshock as well as in front of the Moon. Keywords: Earth foreshock; reflected protons; solar wind proton velocity recon- struction; deceleration; ULF waves 1

Coronal Mass Ejections (CMEs) are considered to be one of the most energetic events in the heliosphere. Capable of inducing geomagnetic storms on Earth that can cause damage to electronics, a pillar which the modern society we live in leans heavily upon. Being able to accurately predict the arrival of CMEs would present us with the ability to issue timely warnings to authorities and commercial actors, allowing for protective measures to be put in place minimizing the damage. In this study the predicted arrival times and speeds from the Drag Based Model (DBM) and Drag Based Ensemble Model (DBEM) were compared to observational data from a set of 12 events containing fast, Earth-directed Halo CMEs and their corresponding shocks. Although DBM was developed to model CME propagation, varying some parameters allow it to be used for estimating shock/sheath arrival. The results presented in this study indicate that on average DBM performs best when the drag-parameter γ is in the range 0.2 ≤ γ ≤ 0.3. However the variability in the results show that determining a universal value of γ for fast CMEs does not increase the consistency in the model's performance. For completeness, further investigation is needed to account for not only halo CMEs. This will allow to test broader range of variation in the DBEM input parameters.

Indiana University-Purdue University Indianapolis (IUPUI) / This dissertation focuses on quantification of submicroscopic iron of different sizes, mineral abundance and grain size of lunar soils using Hapke's radiative transfer model. The main objective is to explore implications of these results for assessing the relative importance of solar wind implantation versus micrometeorite impacts for lunar space weathering as well as three hypotheses (solar wind deflection, comet impact and dust transport) for swirl formation on the Moon. Results from this study can help to make connections between ordinary chondritic meteorites and asteroids, and put physical and chemical constraints on heating processes in the early solar system.

<p>Space weathering refers to the gradual spectral, microstructural, and chemical alteration of airless planetary regoliths due to their exposure to the harsh environment of outer space. Solar wind irradiation and micrometeoroid impacts are the primary space weathering processes at work in our solar system. Although the microstructural and compositional effects of space weathering are small, occurring at the sub-micron scale in individual regolith grains, their collective impact on the spectral signature of planetary surfaces is critical. Space weathering is known to change the slope, albedo, and strength of absorption band features of reflectance spectra acquired by ground- and spacecraft-based instrumentation. In this way, space weathering impedes our ability to determine planetary surface compositions from remote sensing data and pair meteorites with their parent bodies. Thanks to decades of research since the Apollo sample return missions, the planetary science community has developed a comprehensive understanding of how space weathering alters the Moon and silicate-rich asteroids. However, the effects of space weathering on primitive, carbon-rich asteroids—which dominate the outer main belt—are more poorly constrained and very complex. This dissertation aims to improve our understanding of how solar wind irradiation and micrometeoroid bombardment modifies the spectral, microstructural, and chemical properties of carbonaceous asteroidal regoliths. To accomplish this goal, this research experimentally simulates constituent space weathering processes in the laboratory on carbon-rich analog materials. A multi-faceted analytical approach including a variety of electron microscopy and spectroscopic techniques is used to probe the spectral, microstructural, and chemical changes induced by experimental space weathering.</p><p>Chapter 1 of this dissertation provides an introduction to space weathering, including a description of the current state of knowledge in the field as well as the motivation for this research. Similarly, chapter 2 provides an overview of the various experimental simulations and coordinated analytical techniques employed in this work. Chapter 3 initiates the discussion of research accomplished during this doctoral program, presenting a detailed characterization of the spectral, microstructural, and chemical effects derived from simulated solar wind irradiation of a carbonaceous asteroid analog material. More specifically, in chapter 1, I perform high flux (~1013 ions/cm2/s), high fluence (1018 ions/cm2) 1 keV H+ and 4 keV He+ irradiation experiments on the Murchison meteorite. Chapter 2 investigates the role of incident ion flux in solar wind space weathering of carbonaceous asteroidal regolith by performing a set of low flux (~1011 ions/cm2/s) and high flux (~1013 ions/cm2/s) H+ and He+ irradiation experiments on Murchison samples. These experiments are the lowest flux solar wind simulations carried out, to date. Finally, chapter 5 presents results from the first <i>combined</i> ion irradiation and heating experiments performed on a carbon-rich analog using in situ transmission electron microscopy (TEM). In situ TEM is a relatively novel technique in the planetary and geological sciences which allows users to observe the physiochemical changes caused by an external stimuli in <i>real time</i>. The experimental approach used in chapter 5 simulates both solar wind irradiation and micrometeoroid impacts, and, thus, probes the cumulative microstructural and compositional modifications induced by these concurrent space weathering processes. In chapters 3 through 5, I compare my results to previous space weathering simulations and observations of lunar and asteroidal returned samples. Findings from this dissertation advance the existing model of space weathering on carbon-rich asteroids, help inform remote sensing observations from the Hayabusa2 and OSIRIS-REx missions which have rendezvoused with C-complex asteroids Bennu and Ryugu, respectively, and provide experimental ground-truth for analyzing returned samples from these missions.</p>