This thesis is dedicated to the theory of solar radar experiments. The Sun exhibits a variety of interesting and complicated physical phenomena, examined mainly through analysis of its radiation. Active solar probing by radar provides an alternative possibility to study the Sun. This concept was tested originally in the 1960's by solar radar experiments at El Campo, Texas, but due to an insufficient level of technology at that time the experimental results were of a poor quality and thus difficult to interpret. Recently, the space weather program has stimulated interest in this topic. New experimental proposals require further development of the theory of solar radar experiments to meet the current knowledge about the Sun and the modern level of technology. Three important elements of solar radar experiments are addressed in this thesis: i) generation of wave turbulence and radiation in the solar corona, ii) propagation of the radar signal to the reflection point, and iii) reflection (scattering) of the incident radar signal from the Sun. It is believed that the radio emission of solar type II and III bursts occurs due to conversion of Langmuir waves, generated by electron beams, into electromagnetic radiation (plasma emission mechanism). The radar signal propagating through the emission source region can get scattered by the Langmuir turbulence and finally deliver the observer insights of the physics of this turbulence. Such process of scattering is considered in this thesis in the weak turbulence limit by means of the wave-kinetic theory. Scattering frequency shifts, scattering cross-sections, efficiency of scattering (the coefficient of absorption due to scattering), optical depths, and the spectra of the scattered signal are estimated. Type II solar radio bursts are known to be associated with the electron beams accelerated by interplanetary shocks. From their dynamic spectra the properties of the shocks and regions in the vicinity of the shock are usually inferred by assuming a plasma emission mechanism. In situ observations of the source region of type II burst, presented in this thesis, suggest that an additional emission mechanism may be present. This mechanism is related to energetic particles crossing the shock front, known in electrodynamics as transition radiation. Plasma density fluctuations are known to scatter radio waves and thus broadening their angular dispersion. In the thesis this process is studied in the solar wind and terrestrial electron and ion foreshocks on the basis of in situ observations of density fluctuations. It is shown that the angular broadening of the radar signal is negligible in this regions. The results of this thesis can be applied for the preparation of future solar radar experiments and interpretation of experimental data.

The Neutral Particle Detector (NPD) is a new type of instrumentation for energetic neutral atom (ENA) diagnostics. This thesis deals with development of the NPD sensor designed as a part of the plasma and neutral particle packages ASPERA-3 and ASPERA-4 on board Mars Express and Venus Express, the European Space Agency (ESA) satellites to Mars and Venus, respectively. It describes how the NPD sensors were designed, developed, tested and calibrated. It also presents the first scientific results obtained with NPD during its operation at Mars. The NPD package consists of two identical detectors, NPD1 and NPD2. Each detector has a 9o x 90o intrinsic field-of-view divided into three sectors. The ENA detection principle is based on the surface interaction technique. NPD detects ENA differential fluxes within the energy range of 100 eV to 10 keV and is capable of resolving hydrogen and oxygen atoms by time-of-flight (TOF) measurements or pulse height analysis. During the calibration process the detailed response of the sensor was defined, including properties such as an angular response function and energy dependent efficiency of each of the sensor sectors for different ENA species. Based on the NPD measurements at Mars the main scientific results reported so far are: - observation of the Martian H-ENA jet / cone and its dynamics, - observations of ENA emissions from the Martian upper atmosphere, - measurements of the hydrogen exosphere density profile at Mars, - observations of the response of the Martian plasma environment to an interplanetary shock, - observations of the H-ENA fluxes in the interplanetary medium.

This thesis is focused on the role of Alfvén waves in the energy transformation and transport in the magnetosphere. Different aspects of Alfvén wave generation, propagation and dissipation are considered. The study involves analysis of experimental data from the Freja, Polar and Cluster spacecraft, as well as theoretical development. An overview of the linear theory of Alfvén waves is presented, including the effects of fnite parallel electron inertia and fnite ion gyroradius, and nonlinear theory is developed for large amplitude Alfvén solitons and structures. The methodology is presented for experimental identification of dispersive Alfvén waves in a frame moving with respect to the plasma, which facilitates the resolution of the space-time ambiguity in such measurements. Dispersive Alfvén waves are identified on field lines from the topside ionosphere up to the magnetopause and it is suggested they play an important role in magnetospheric physics. One of the processes where Alfvén waves are important is the establishment of the field aligned current system, which transports the energy from the reconnection regions at the magnetopause to the ionosphere, where a part of the energy is dissipated. The main mechanism for the dissipation in the top-side ionosphere is related to wave-particle interactions leading to particle energization/heating. An observed signature of such a process is the presence of parallel energetic electron bursts associated with dispersive Alfvén waves. The accelerated electrons (electron beams) are unstable with respect to the generation of high frequency plasma wave modes. Therefore this thesis also demonstrates an indirect coupling between low frequency Alfvén wave and high frequency oscillations.

The space around Earth, confined in the terrestrial magnetosphere, is to some extent shielded from the Sun's solar wind plasma and magnetic field. During certain conditions, however, strong interaction can occur between the solar wind and the magnetosphere, resulting in magnetospheric activity of several forms, among which substorms and storms are the most prominent. A general framework for how these processes work have been outlayed through the history of research, however, there still remain questions to be answered. The most striking example regards the onset of substorms, where both the onset cause and location in the magnetosphere/ionosphere are still debated. These are clearly not easily solved problems, since a substorm is a global process, ideally requiring simultaneous measurements in the magnetotail and ionosphere. Investigated in this work are temporal and spatial scales for substorm and convection processes in the Earth's magnetosphere and ionosphere. This is performed by combining observations from a number of both ground-based and spacecraft-borne instruments. The observations indicate that the magnetotail's cross-section is involved to a larger spatial extent than previously considered in the substorm process. Furthermore, convection changes result in topological changes of the magnetosphere on a fast time scale. The results show that the magnetosphere is, on a global magnetospheric scale, highly dynamic during convection changes and ensuing substorms.

<p>The turbulen flow in an asymmetric diffuser has been en studied by the means of Reynold average Navier-Stokes equations with both differential and explict algebraic expressions to model the Reynolds stress tensor. Modifications to the differential stress model have been derived, using the inverse turbulence timescale to obtain the dissipation of turbuence kinetic energy. The explicit algebraic Reynolds stress model has been used in combination with a two-equation platform to close the system of equations. Modifications made to the transport equation for the inverse turbulence timescale has made it possible to substantially relax the deman on near-wall resolution of this quantity. The rapid growth wth present in the original formulation can be treated as an explicit function of the wall-normal distance. In order to use the new formulation for the transport equation, an equation has as been derived to obtain the shortest distance bettwee a point and the closest wall, regardles of the geometric complexity of the domain. An explicit algebraic expression to model the passive scalar flux vector has been investigated using a comparison with a standard eddy-diffusivity model in the asymmetric diffuser. Results show a substantial improvement of the complexity of the scalar field and scalar flux vector in sepaarated flows. Automated code generation has been used in all the above studies to generate versatile model testing tools for general two-dimensional geometries. Finite element formulations are used for these tools.</p>

Euclid is a medium class mission designed to study the geometry of dark universe. It will work in the visible and near infrared imaging &amp; spectroscopy for a lifetime of 6 years down to the magnitude of mAB = 24.5 with Visible Imager Instrument (VIS) and mAB = 24 with Near Infrared Spectrometer and Photometer instrument in Y, J &amp; H broadband filters. The current survey design will avoid ecliptic latitudes below 15 degrees, but the observation pattern in repeated sequences of four blocks with four broad-band filter seems well-adapted to Solar System object detection. The aim of this thesis is to simulate the Solar System Objects (SSOs) for Near Infrared Spectrometer and Photometer (NISP) instrument and measure the flux/magnitude &amp; position of these moving objects. The simulation of Solar System Objects is implemented in with simulator Imagem using the sky position, velocity, direction of movement and magnitude with respect to band of the objects. The length of the trail is determined using exposure time and after that the sky position is evolved for each band filter. The output images showed the trail of objects which is 2 to 10 pixels long in case of Near Infrared Spectrometer and Photometer instrument. To find out the flux distribution in the trail, the differential photometry is performed. The variation in magnitude was observed at least of 1% to 3% of the magnitude which may also implies that variation in brightness of objects can be observed with the velocity. To detect the moving objects, differential astrometry is also performed, which provides the catalogue with the information of position and proper motion of the objects as well as an image is also generated which showed the detected and undetected objects from all bands in one image.

This thesis addresses the complexities in the design of System of Systems, by providing a flexible, case independent method to analyse and rank the alternatives that are capable of performing the desired missions or operations assigned by decision makers. Although its methods involve only low-fidelity models, these proved to be the best choice as the design space created and, consequently, the number of analysis grow explosively with the increase of available options to perform the required tasks. This is due to the combinatory approach used in the generation of the design space. Another goal is to provide a demonstration of possible improvements with the addition of ontologies to the early stages of design, especially when complex solutions are expected. This also diminishes the probability of human error by decreasing the amount of work demanded when adding alternatives or changing their characteristics, displaying again the feasible application of knowledge based and automated solutions to the engineering design process. With these advantages, the flexibility of altering the set of inputs is enhanced, adding to the resilience of the framework, as it can be attached to any available compatible ontology and perform in that specific domain without hindrance. Due to the lack of techniques and the probable cost of these once made available, the evaluation of emergence is not considered in this work, and is not reccomended to be directly done once ready for use, at least not on the full result array. Moreover, the modular implementation of the framework makes the exchange of functions a rather simple task, enabling users to adapt it to their own needs. Some immediate implementations are mentioned to greatly improve the general performance and relevance of results provided.

This report is a part of a thesis work at the division of Fluid and Mechatronic Systems(Flumes) at Linkoping University. The aim of this thesis is to build a robust, advanced, simple, easy to maintain, easy to develop and user-friendly program for the general aviation aircraft conceptual design. The program name is FLEX (FlumesExcel). The program was developed based on the most famous references in this eld such as Raymer [1], Gudmundsson [2] and Torenbeek [3]. Dierent methods and equations were evaluated to choose the best. In case there is no way to evaluate the methods, they were all implemented and the user has the ability to choose the desired one. Microsoft Excel was chosen to build the program and Excel VBA was used to build macros and functions in order to serve the objectives of the program. This report explains the used methods, the implementation way, and the program arrangement. It also shows how the results are presented in the program and provides the user with notes about the program using and its limits. The author supposes that the reader is familiar with the basic aerodynamic and aircraft design knowledge and nomenclatures. In order to not extend the report, some methods and theories are referred to the references without deep explanation. In case the used equations were derived by the author, they are explained in detail.

Learning from Demonstration (LfD) has been used in robotics research for the last decades to solve issues pertaining to conventional programming of robots. This framework enables a robot to learn a task simply from a human demonstration. However, it is unfeasible to teach a robot all possible scenarios, which may lead to e.g. the robot getting stuck. In order to solve this, a search is necessary. However, no current work is able to provide a search approach that is both simple and general. This thesis develops and evaluates a new framework based on LfD that combines both of these aspects. A single demonstration of a human search is made and a model of it is learned. From this model a search trajectory is sampled and optimized. Based on that trajectory, a prediction of the encountered environmental forces is made. An impedance controller with feed-forward of the predicted forces is then used to evaluate the algorithm on a Peg-in-Hole task. The final results show that the framework is able to successfully learn and reproduce a search from just one single human demonstration. Ultimately some suggestions are made for further benchmarks and development.

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