L'instrument AMBRE 1 (Active Monitor Box of Electrostatic Risks) est un spectromètre de mesure du plasma (ions positifs et électrons) composé de deux têtes de mesure qui a été lancé à bord du satellite Jason 3 en Janvier 2016. A travers la mesure du plasma thermique (énergies comprises entre ~0 et 35 keV) cet instrument permet, d'une part, de déterminer la charge électrostatique des satellites et les populations en étant à l'origine pour répondre à des enjeux opérationnels, et d'autre part, de caractériser les environnements plasma magnétosphériques avec des enjeux scientifiques. La réduction des caractéristiques physiques (poids, consommation électrique et encombrement) des instruments AMBRE est un enjeu clé dans le but de rendre son embarquement systématique sur les plateformes satellites (scientifiques comme commerciales) et ainsi étendre le réseau de ce type de mesures dans l'environnement terrestre. L'objectif de cette thèse porte sur la conception, le développement et la réalisation d'un prototype d'instrument AMBRE 2 répondant à ces enjeux, tout en améliorant les performances scientifiques. Cette nouvelle génération d'instrument repose sur l'utilisation d'une seule tête qui mesure les deux types de population de manière alternée dans le temps. L'étude de chaque sous-système d'AMBRE 2 a permis de trouver les meilleurs compromis permettant de mesurer les deux types de population tout en minimisant les ressources allouées à l'instrument. Un prototype a été réalisé et testé sous vide avec un canon à ions et un canon à électron courant octobre 2017 afin de valider son principe de fonctionnement. / The Active Monitor Box of Electrostatic Risks (AMBER) is a double-head thermal plasma (positive ions and electrons) electrostatic analyser that was launched onboard the Jason-3 spacecraft in January 2016. By measuring the thermal plasma (in the energy range ~0 - 45 keV) the instrument permits, on the one hand, to determine the spacecraft electrostatic charging and the populations at its origin with operational stakes, and, on the other hand, to characterize the magnetospheric plasma environments with scientific goals. Reducing the physical resources (weight, electric consumption, and volume) of the AMBRE line of instrument is key to a potential systematic embarkation onboard various platforms (scientific or commercial), thereby augmenting the constellation of such measurements in near-Earth space. The goal of the present thesis is to conceive, develop and build an AMBRE 2 instrument prototype that meets these goals while augmenting its scientific capabilities. This new generation of instrument relies on the use of a single head which alternatively measures ions and electrons. Each AMBRE 2 sub-system was studied and designed using the best trade-off solution between overall resources and capabilities. A prototype has been built and tested in a vacuum chamber with ion and electron beams in October 2017 in order to validate its functionality.

The original objectives of this thesis were to use the new PolarDARN radars to study the convection patterns at high latitudes and to attempt to explain them in terms of reconnection. Because the IMF is important in reconnection, studies of the Interplanetary Magnetic Field (IMF) components Bx, By and Bz were done. The study showed that <|Bz|> was lower by 21.5% than <|By|> from Jan. 2006 to Dec. 2008, so By was expected to play an important role in reconnection. The IMF, spiral angle, and the amount of warping of the solar magnetic field in interplanetary space decreased slightly during this 36-month period. The decrease in IMF was a more sensitive indicator of the solar minimum than the decrease in the 10.7 cm solar microwave flux.<p> A solar magnetic sector boundary study from the Jan 1, 2007 Dec 31, 2008 interval showed the occurrence of four or two sectors in a synodic solar rotation cycle. A sector boundary crossing frequently takes place in less than 3 hours. The transition from four sectors to two sectors is surprisingly smooth, in that no interruption in the 27-day synodic period occurs. A superposed epoch analysis of solar wind speed near sector boundary crossings showed a speed minimum about half a day before the crossing, and a maximum about two days after the crossing. The standard deviation reached a minimum at about the same time as the velocity. The sector boundary study also showed that, since Dec. 2007, there were six roughly 27-day synodic solar rotation cycles near spring equinox when away field dominated, and that the following seven 27-day cycles close to the autumnal equinox were dominated by toward field. This is consistent with the quasi-sinusoidal annual magnetic sector polarity oscillations that occur for about three years during solar minimum. These oscillations are due to the mainly dipolar magnetic field which is roughly aligned with the Suns axis, tilted 7.25° from the normal to the ecliptic plane. The three-year oscillation for the present minimum between Solar Cycles 23 and 24 appeared to begin in Dec. 2007. For the past four solar minima, an El Nino event has occurred during the last of the three oscillations, and the El Nino and sinusoidal magnetic oscillation ended together. The new solar cycle began about 6 months before that. During the past eight years, a new 3D topological null-separator formulation of magnetic reconnection and its effect on convection has been led by Dr. M. Watanabe in ISAS at the University of Saskatchewan. This formulation includes two types of interchange reconnection (Russell and Tanaka) as well as the traditional Dungey reconnection. For conditions when the IMF clock angle was within 30° of a Bz+ dominant convection, the new reconnection model shows that the convection can be driven strictly by the two types of interchange reconnection. The model predicts the existence of a reciprocal cell on closed field lines and an interchange merging cell surrounding an interior lobe cell. The construction of the PolarDARN radars at Rankin Inlet and Inuvik, completed in December, 2007, allowed polar cap convection to be measured for predominantly Bz+ conditions. The existence of the two predicted features was confirmed. This also required that satellite data be analyzed to determine the location of the open-closed-field-line-boundary (OCFLB). Several PolarDARN studies are represented to show convection for different IMF clock angles and seasons.

The original objectives of this thesis were to use the new PolarDARN radars to study the convection patterns at high latitudes and to attempt to explain them in terms of reconnection. Because the IMF is important in reconnection, studies of the Interplanetary Magnetic Field (IMF) components Bx, By and Bz were done. The study showed that <|Bz|> was lower by 21.5% than <|By|> from Jan. 2006 to Dec. 2008, so By was expected to play an important role in reconnection. The IMF, spiral angle, and the amount of warping of the solar magnetic field in interplanetary space decreased slightly during this 36-month period. The decrease in IMF was a more sensitive indicator of the solar minimum than the decrease in the 10.7 cm solar microwave flux.<p> A solar magnetic sector boundary study from the Jan 1, 2007 Dec 31, 2008 interval showed the occurrence of four or two sectors in a synodic solar rotation cycle. A sector boundary crossing frequently takes place in less than 3 hours. The transition from four sectors to two sectors is surprisingly smooth, in that no interruption in the 27-day synodic period occurs. A superposed epoch analysis of solar wind speed near sector boundary crossings showed a speed minimum about half a day before the crossing, and a maximum about two days after the crossing. The standard deviation reached a minimum at about the same time as the velocity. The sector boundary study also showed that, since Dec. 2007, there were six roughly 27-day synodic solar rotation cycles near spring equinox when away field dominated, and that the following seven 27-day cycles close to the autumnal equinox were dominated by toward field. This is consistent with the quasi-sinusoidal annual magnetic sector polarity oscillations that occur for about three years during solar minimum. These oscillations are due to the mainly dipolar magnetic field which is roughly aligned with the Suns axis, tilted 7.25° from the normal to the ecliptic plane. The three-year oscillation for the present minimum between Solar Cycles 23 and 24 appeared to begin in Dec. 2007. For the past four solar minima, an El Nino event has occurred during the last of the three oscillations, and the El Nino and sinusoidal magnetic oscillation ended together. The new solar cycle began about 6 months before that. During the past eight years, a new 3D topological null-separator formulation of magnetic reconnection and its effect on convection has been led by Dr. M. Watanabe in ISAS at the University of Saskatchewan. This formulation includes two types of interchange reconnection (Russell and Tanaka) as well as the traditional Dungey reconnection. For conditions when the IMF clock angle was within 30° of a Bz+ dominant convection, the new reconnection model shows that the convection can be driven strictly by the two types of interchange reconnection. The model predicts the existence of a reciprocal cell on closed field lines and an interchange merging cell surrounding an interior lobe cell. The construction of the PolarDARN radars at Rankin Inlet and Inuvik, completed in December, 2007, allowed polar cap convection to be measured for predominantly Bz+ conditions. The existence of the two predicted features was confirmed. This also required that satellite data be analyzed to determine the location of the open-closed-field-line-boundary (OCFLB). Several PolarDARN studies are represented to show convection for different IMF clock angles and seasons.

The objective of this research is the statistical study of space weather e ects on im- age detectors in Low Earth Orbit. The Hubble Space Telescope is used as a resource for acquiring proton a ected images for statistical analysis. For the purpose of the present work, the space weather environment will consist of cosmic as well as solar proton particles. The proton occurrences evident in images from the Hubble Charge Coupled Device (CCD) have been used to calculate the probability of proton events, which is related to the local space weather particle ux. The proton particles transfer energy to the CCD silicon, which ultimately results in measured signal that is not originating from photon illumination. The signal due to the proton interactions is rst separated from the noise contribution and subsequently used in the determi- nation of a pulse height probability distribution. Separation of the noise from the proton events also leads to the measurement of proton streak lengths and orientations along with the associated probability distributions. The directionality of the space weather environment in Low Earth Orbit is examined using the distribution of proton streak angles. Statistics found from the Hubble are also used as a starting point for simulations that create synthetic proton signal images. The distributions resulting from the Hubble CCD analysis give the probability of the: number of proton events, which is related to the ux of the space weather protons; energy of proton events, which allows estimates of damaging proton interactions; length of proton streaks on the CCD, which shows the relative probability of a long traversing proton event; angle of proton event, which indicates the directionality of the space weather environment.

Made available in DSpace on 2014-06-11T19:30:31Z (GMT). No. of bitstreams: 0 Previous issue date: 2010-11-03Bitstream added on 2014-06-13T19:00:44Z : No. of bitstreams: 1 dalpoz_wr_dr_prud.pdf: 7310354 bytes, checksum: 0dad0c578066121061e36552e4e9f136 (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / O erro devido à ionosfera nas observáveis GNSS (Global Navigation Satellite System) é diretamente proporcional à densidade de elétrons presente na ionosfera e inversamente proporcional a frequência do sinal. Da mesma forma que no posicionamento por ponto, os resultados obtidos no posicionamento relativo são afetados pelo efeito sistemático da ionosfera, que é uma das maiores fontes de erro no posicionamento com GNSS. Mesmo considerando que parte dos erros devido à ionosfera é cancelada na dupla diferenciação, a ionosfera pode causar fortes impactos no posicionamento relativo. O problema principal neste método de posicionamento é a variação espacial na densidade de elétrons, que pode ocorrer em função de vários fatores, tais como hora local, variação sazonal, localização do usuário, ciclo solar e atividade geomagnética. Dependendo das condições do clima espacial, que é controlado pelo Sol, a atividade geomagnética pode ser alterada de forma significativa, dando origem a uma tempestade geomagnética. Nesta pesquisa foram avaliados os efeitos da ionosfera no posicionamento relativo, com observações GNSS da fase da onda portadora (L1), nas regiões ionosféricas de latitude média e alta e na região equatorial. Nas duas primeiras regiões foram analisados os efeitos da ionosfera em períodos de irregularidades, decorrentes de tempestades geomagnéticas. Na região equatorial, que engloba o Brasil, foram analisados os efeitos da ionosfera em função da variação diária e sazonal. No processamento dos dados GNSS foi utilizado o GPSeq, que processa os dados na forma recursiva e fornece os Resíduos Preditos da Dupla Diferença da Fase (RPDDF)... / The error caused by ionosphere on GNSS (Global Navigation Satellite System) is directly proportional to the density of electrons from ionosphere and inversely proportional to the frequency squared of the signal GNSS. As in the case of point positioning, results in relative positioning are affected by systematic effect from ionosphere, which is one of major error sources in the GNSS positioning. Although some errors caused by ionosphere are canceled in double difference, strong impacts may be caused by ionosphere on the relative positioning. In this positioning the main problem is the spatial variation in electron density that can occur due local time, seasonal variation, user location, solar cycle, geomagnetic activity, etc. Depending on the conditions of space weather, in which is controlled by the Sun, the geomagnetic activity can be changed inducing geomagnetic storms. In this research the effects from ionosphere has been evaluated in GNSS relative positioning using L1 carrier phase observations, at the three regions of the ionosphere: middle and high latitudes and equatorial region. In regions of middle and high latitudes have been analyzed the effects from ionosphere in irregularities periods, caused by geomagnetic storms. In the equatorial region, including Brazil, have been analyzed the effects from ionosphere according daily and seasonal variation. In the processing GNSS data has been used GPSeq software. This software processes the data in a recursive form and provides the Predicted Residual of Carrier Phase Double Difference (PRCPDD) ... (Complete abstract click electronic access below)

Ce travail porte sur l’anomalie de l’Atlantique Sud (SAA anglais). Nous avons étudié cette anomalie du champ magnétique principal à partir de données satellitaires afin de mieux connaître les différentes sources de ses variations temporelles. Nous avons appliqué l’analyse en composantes principales (PCA) à des données de flux de particules, de bruit d’un lidar embarqué et à des séries temporelles d’observatoires magnétiques virtuels - séries construites à partir de mesures satellitaires du champ géomagnétique. Les données de flux de particules proviennent de trois satellites de la série POES de la NOAA (POES 10, 12 et 15) ainsi que du satellite Jason-2 du CNES et de la NASA. Nous utilisons aussi le bruit affectant le lidar CALIOP du mini-satellite CALIPSO (CNES/NASA) comme substitut au flux de particules chargées heurtant ce satellite. Pour l’information géomagnétique, deux jeux de données d’observatoires virtuels construits à partir d’enregistrements des satellites CHAMP et Swarm ont été utilisés. Ces deux ensembles différents de données apportent des éclairages complémentaires sur l’anomalie de l’Atlantique Sud. L’analyse en composantes principales des données de flux de particules a permis de distinguer différents modes de variabilité, dus au soleil d’une part et au champ magnétique principal d’autre part. Le cycle solaire de 11 ans affecte à la fois le flux total de particules énergétiques à l’aplomb de l’anomalie de l’Atlantique Sud et leur distribution dans les différentes ceintures de radiation internes. Le champ magnétique principal, qui provient du noyau liquide de la Terre, est responsable d’une lente dérive de l’anomalie de l’Atlantique Sud et par ricochet de la région où il y a un flux intense de particules énergétiques. Une fois déconvolué le rôle du champ magnétique principal, on distingue deux composantes que l’on peut associer sans ambiguïté au cycle solaire. Sur des temps plus longs, nous avons finalement pu mettre en évidence une tendance dans le flux total de particules dans la région de l’Atlantique Sud. Peu d’analyses globales des modes de variabilité du champ interne ont été entreprises. Notre étude vise aussi à combler ce manque. L’analyse en composantes principales permet d’extraire jusqu’à trois modes d’origine interne et un mode annuel combinant contributions interne et externe. Ce dernier mode a une géométrie principalement quadrupolaire et zonale. Le premier des modes purement internes explique l’essentiel de la variabilité du champ et correspond à la variation séculaire moyenne au cours de l’intervalle de temps étudié. Il s’interprète principalement comme la variation de la partie du champ géomagnétique représentée par un dipôle qui serait de plus en plus décalé par rapport au centre de la Terre en direction de l’Asie du Sud-Est et qui serait aussi incliné par rapport à l’axe de rotation. Ainsi, ce simple modèle nous a été utile à la fois pour rendre compte du flux de particule au dessus de l’anomalie de l’Atlantique Sud et pour interpréter la variation du champ géomagnétique à l’échelle globale. / This work focus on the study of the South Atlantic Anomaly (SAA) of the main magnetic field from satellite data, aiming at identifying different sources of variability. This is done by first applying the Principal Component Analysis (PCA) method to particle flux and dark noise data and then to Virtual Observatories (VOs) time series constructed from satellite magnetic records. Particle flux data are provided by three POES NOAA satellites (10, 12 and 15) and the Jason-2 satellite. Dark noise data, which can be interpreted as a proxy to particle flux, are provided by the CALIOP lidar onboard the CALIPSO satellite. The magnetic field information is used in the form of time series for VOs, which were computed from both CHAMP and Swarm data as two separate datasets. The two different groups of data provide different views of the South Atlantic Anomaly. Applying PCA to particle flux data on the SAA produces interesting modes that can be related with specific physical processes involved with the anomaly. The main sources that drive these modes are the Earth’s magnetic field and the Sun. The Sun’s 11-year cycle is a well-known quasi-period of solar activity. This work shows how it clearly affects the evolution of the energetic particles trapped in the inner Van Allen belt, by modulating both their total number and their distribution among different L-shells. The way particles become trapped and move near-Earth is also dictated by the main magnetic field geometry and intensity and so a good understanding of its variation allows for a better description of the evolution of these particles. The main magnetic field, with origin in the Earth’s liquid core, is responsible for a slow drift of the anomaly, associated to the Westward drift of several features of the main field. Changing the frame of reference to that of the eccentric dipole, we were able to identify two separate modes associated with the variability of the solar activity. On longer time-scales, we also observed a linear trend in the spatial evolution of the particle flux. A global analysis of variability modes of the Earth’s magnetic field has not been often addressed. This study also contributes to fill this gap. By decomposing satellite records of the magnetic field into PCA modes, we retrieved modes of internal origin and modes with large external contributions, with no a-priori considerations. An annual signal has been identified and associated with mainly external sources. It exhibits an interesting geometry dominated by a zonal quadrupolar geometry. As for the internal source, three separate modes were obtained from the longest time series analysed. The first of these modes explains most of the variability of the field and represents the mean secular variation. It is closely modelled by an eccentric tilted dipole moving away from the Earth’s center and toward under East Asia. As this study shows, this simple model turns out to be a useful tool that can be used both on regional studies of the SAA and on global studies of the geomagnetic field.

L’irradiance spectrale solaire (SSI) dans la bande ultraviolette est un paramètre-clé pour la spécification de la moyenne et la haute atmosphère terrestre. Elle est requise dans de nombreuses applications en météorologie de l’espace, et aussi pour l’étude du climat. Or les observations souffrent de plusieurs défauts : manque de couverture spectrale et temporelle permanente, dégradation des capteurs, désaccords entre les instruments, etc. Plusieurs modèles de reconstruction de la SSI ont été développés pour pallier à ces difficultés. Chacun souffre de défauts, et la reconstruction du spectre en-dessous de 120nm est un réel défi. C’est dans ce contexte que nous avons développé un modèle empirique, qui recourt au champ magnétique photosphérique pour reconstruire les variations du spectre solaire. Ce modèle décompose les magnétogrammes solaires en différentes structures qui sont classées à partir de leur aire (et non sur la base de leur intensité, comme dans la plupart des autres modèles). La signature spectrale de ces structures est déduite des observations, et non pas imposée par des modèles de l’atmosphère solaire. La qualité de la reconstruction s’avère être comparable à celle d’autres modèles. Parmi les principaux résultats, relevons que deux classes seulement de structures solaires suffisent à reproduire correctement la variabilité spectrale solaire. En outre, seule une faible résolution radiale suffit pour reproduire les variations de centre-bord. Enfin, nous montrons que l’amélioration apportée par la décomposition du modèle en deux constantes de temps peut être attribuée à l’effet des raies optiquement minces. / The spectrally-resolved radiative output of the Sun (SSI) in the UV band, i.e. at wavelengths below 300 nm, is a key quantity for specifying the state of the middle and upper terrestrial atmosphere. This quantity is required in numerous space weather applications, and also for climate studies. Unfortunately, SSI observations suffer from several problems : they have numerous spectral and temporal gaps, instruments are prone to degradation and often disagree, etc. This has stimulated the development of various types of SSI models. Proxy-based models suffer from lack of the physical interpretation and are as good as the proxies are. Semi-empirical models do not perform well below 300 nm, where the local thermodynamic equilibrium approximation does not hold anymore. We have developed an empirical model, which assumes that variations in the SSI are driven by solar surface magnetic flux. This model proceeds by segmenting solar magnetograms into different structures. In contrast to existing models, these features are classified by their area (and not their intensity), and their spectral signatures are derived from the observations (and not from models). The quality of the reconstruction is comparable to that of other models. More importantly, we find that two classes only of solar features are required to properly reproduce the spectral variability. Furthermore, we find that a coarse radial resolution suffices to account for geometrical line-of-sight effects. Finally, we show how the performance of the model on different time-scales is related to the optical thickness of the emission lines.

No description available.

La couronne solaire est un milieu très dynamique : instabilités du champ magnétique, qui structure le plasma, conduit à l'accélération et le chauffage des particules chargées et à l'éjection de grandes structures dans l'héliosphère, les émissions de masse coronale (CME, selon ces sigles en anglais). Ces structures magnétiques éjectées peuvent interagir avec le champ magnétique de la Terre et affecter le plasma de l'environnement. Ces structures conduisent également à l'induction des courants électriques dans le sol à des latitudes élevées. L'étude de l'origine et de la propagation de ces émissions est d'intérêt pour l’astrophysique dans l’encadre des applications générales et pour la météorologie de l’espace. La compréhension des processus de base est une condition importante pour l'élaboration des méthodes de prévision des arrivées de ces perturbations en utilisant des observations de la couronne solaire. Les CMEs sont observées et étudiées à travers des images coronographiques. La limitation fondamentale du coronographe est qu'il montre la couronne seulement dans le plan du ciel, donc il bloque, forcément, la vue sur le disque solaire. Mais le geoefficacité d'une CME dépend essentiellement de la proximité à la ligne Soleil- Terre et de l'évolution dans la basse couronne que ne sont pas visibles à travers des observations coronographiques. Un des problèmes est la difficulté d’estimer l'arrivée d'une CME à la Terre, parce que les mesures avec coronographes directes de la vitesse de propagation des CMEs qui est dirigée vers la Terre ne sont pas possibles dans la ligne Soleil-Terre. Cette thèse présente l'étude des CMEs en trois étapes : (1) une étude de cas de l'évolution CME dans la bassecouronne et son rôle dans l'accélération des particules, (2) la relation entre la polarisation de l'émission de sursauts radio de type IV associées à CMEs dans la couronne et l'orientation du champ magnétique observé quand les CMEs arrivent à la Terre, et (3) des estimations radiatives de la vitesse des CMEs pour les prévisions des temps d’arrivée des CMEs à la Terre. Imagerie en utilisant des émissions radio dans la basse couronna peut montrer les signatures des CMEs sur le disque solaire. Des études précédentes avec le Radiohéliographe de Nançay (NRH) suggèrent, en fait, que les images de radio aux longueurs d'onde métriques peuvent suivre l'évolution des CMEs bien avant qu'ils deviennent visibles dans la couronne. Le diagnostic de l'évolution CME dans la basse couronne développée dans ce travail a été illustrée par l'étude de l'événement éruptif du 26 Avril 2008, qui a offert une occasion unique d'étudier le lien physique entre une seule CME bien identifiée, l'accélération des électrons tracé par émission radio, ainsi que la production des particules énergétiques solaires (SEP, selon ces sigles en anglais) observées dans l'espace. Nous effectuons une analyse détaillée en combinant les observations radio (NRH et DAM, Wind / WAVES spectrographe) et les observations de la couronne avec des satellites dans EUV et lumière blanche, ainsi que des mesures ‘in situ’ des particules énergétiques près de 1UA (satellites SoHO et STEREO). En combinant des images prises à partir de plusieurs points de vue, nous avons pu déduire l'évolution 3D en fonction du temps du front de l’éjection de mass qui s’est développée autour de l’éruption de la CME. Enfin, nous avons identifié, à partir des observations radio et SEP, trois régions différentes d'accélération des particules associées à l'évolution de la même CME, séparés en longitude environ 140°. / The solar corona is a highly dynamical medium: instabilities of the magnetic field, which structure the plasma, lead to the acceleration and heating ofcharged particles and to the ejection of large structures into the heliosphere, the Coronal Mass Ejections (CMEs). These ejected magnetic structures can interact with the Earth's magnetic field and thereby affect the plasma environment and the high atmosphere of the Earth. Studying the origin and propagation of CMEs is of interest for both astrophysics in general and space weather applications. The understanding of the basic processes is indeed a pre-requisite for developing prediction methods of potentially geo-effective disturbances based on observations of the solar corona.The CMEs are observed and studied primarily through coronographic images. The basic limitation of the coronagraph is that it shows the corona only in the plane of the sky, and blocks by necessity the view on the solar disk. But the geoeffectiveness of a CME depends crucially on the proximity to the Sun-Earth line and the measurements of the propagation speed, onset and early evolution of CMEs in the low corona are not accessible to coronographic observations. This thesis presents the study of CMEs in three different stages: (1) a case study of the CME evolution in the low corona and of its role in particle acceleration, (2) the relationship between the polarisation of the type IV radio emission associated with Earth-directed CMEs in the corona and the orientation of the magnetic field observed as the CMEs arrive at the Earth, and (3) the estimation of the travel times of CMEs to the Earth. Radio imaging with the Nancay Radioheliograph (NRH) suggest that radio images at metric wavelengths track the early evolution of CMEs well before they become visible in the corona. The examination of the CME evolution in the low corona developed in this work was illustrated through the study of the eruptive event on 26 April 2008, which offered a unique opportunity to investigate the physical link between a single well-identified CME, electron acceleration as traced by radio emission, and the production of solar energetic particles (SEPs) observed in space. We conduct a detailed analysis combining radio observations (NRH and Decameter Array, Wind/WAVES spectrograph) with remote-sensing observations of the corona in extreme ultraviolet (EUV) and white light as well as in-situ measurements of energetic particles near 1AU (SoHO and STEREO spacecraft). By combining images taken from multiple vantage points we were able to derive the time-dependent evolution of the 3D pressure front developing around the erupting CME. Finally, we identified, from the radio and SEP observations, three different particle acceleration regions associated to the evolution of the same CME, separated in longitude by about 140$^\circ$. The observations for this event showed that it is misleading to interpret multi-spacecraft SEP measurements in terms of one acceleration region in the corona.

This work describes the design and implementation of space weather related phenomena within the interactive astro-visualization software OpenSpace. Data sets from the Community Coordinated Modelling Center (CCMC) at the National Aeronautics and Space Administration (NASA) were used to implement time-varying high-resolution solar imagery from space observatory spacecraft and time-varying field lines from the different models produced at the CCMC. The obtained results were used to take an audience on an interactive journey through the solar system, at the world’s first ever live planetarium show about space weather.