Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 33 for “"Solar Corona"”.
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The solar corona: modeled, discretized, visualized
… texture is the visually dominant feature of the solar corona---the plasma that extends from the solar surface into space. These coronal fibers can be modeled as magnetic filaments whose shape is governed by the magnetohydrostatic equation. The first goal of this dissertation is to rigorously …
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Extreme Ultraviolet Spectroscopy of the Solar Corona
… Extreme Ultra-Violet (EUV) observations of the solar corona, obtained by the Coronal Diagnostic Spectrometer (CDS) instrument on board the NASA/ESA Solar and Heliospheric Observatory (SOHO) are presented. The CDS instrument for the first time has provided the opportunity of observing a large …
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Electron acceleration at localized wave structures in the solar corona
… and violent explosions in the case of solar flares. During flares, a huge amount of the stored magnetic energy is suddenly released and a substantial part of this energy is carried by the energetic electrons, considered to be the source of the nonthermal radio and X-ray radiation. One …
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Phenomena in the Solar Corona: characteristic structure and dynamic evolution
… of multiple phenomena that exist within the solar corona. The structures explored in this work cover a range of sizes from a small-scale X-ray bright point (<10 Mm), to medium-scale coronal loops(10–100 Mm), and finally to a large-scale prominence (>100 Mm). Observational data and numerical …
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Propagation of energetic electrons in the solar corona observed with LOFAR
… imaging and spectroscopic observations of solar type III radio bursts at low radio frequencies in the range from 30 to 80 MHz. Solar type III radio bursts are understood as result of the beam-plasma interaction of electron beams in the corona. The Sun provides a unique opportunity to study …
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Particle acceleration at null-point current sheets in the solar corona
Energetic events in the solar corona include solar flares and coronal mass ejections (CMEs), which can have a significant effect on Earth’s orbital infrastructure. Learning how non-thermal energy is built-up, stored and released in the corona is crucial for understanding and predicting these …
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Ultraviolet and EUV studies of selected structures in the solar corona
New UV and EUV observations of off-limb and upper solar corona made by the UltraViolet Coronagraph Spectrometer (UVCS) and the Coronal Diagnostic Spectrometer (CDS) on SOHO (Solar and Heliospheric Observatory) are presented in this thesis. These data were used to establish the physical properties, …
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Investigating our dynamic solar corona from near Sun to 1 AU
… thesis, we study two areas of high interest in solar physics: the propagation of coronal mass ejections (CMEs); and the heating and thermal evolution of coronal loops. In our study of CMEs, two separate techniques are employed to derive the three-dimensional (3-D) position angles and kinematic …
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Solar Sailing Adaptive Control Around the Earth-Moon Lagrange Point L4 for Stellar Observations
… as well as our understanding of shocks due to Coronal Mass Ejections and large coronal magnetic reconnection, a solar sailing approach is proposed to separately capture lunar occultations and observe the solar corona from L<sub>4</sub> of the Earth-Moon system. Single and multiple shooting …
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Numerical methods for solar tomography in the STEREO era
… estimates of physical parameters in the solar corona. We focus on methods for both global dynamic estimation of the coronal electron density and estimation of local transient phenomena, such as coronal mass ejections, from empirical observations acquired by instruments onboard the STEREO …
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Catastrophic cooling in solar coronal loops : thermal instability as a road to complex evolution
… have revealed the highly dynamic nature of the solar corona and enabled us to study physical processes in the outer atmosphere of our mother star in great detail. This thesis deals with dynamic processes in coronal loops, i.e. magnetic structures which may be thought of as the elementary …
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Perpendicular Ion Heating by Low-frequency Alfven-wave Turbulence
<p>Determining the mechanisms that heat the solar corona is a fundamental problem in heliospheric physics. One of the proposed models is based on low-frequency Alfven waves (o << O i) launched from the coronal base. Theoretical studies and numerical simulations have shown that Alfven-wave low-beta …
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Coronal magnetic energy release by current sheet reconnection
… investigate the rapid release of energy in the solar corona, with a particular view to understanding the solar flare in which magnetic reconnection is thought to play a key role. A review of existing reconnection solutions is given in Chapters 2 and 3, with new analytic and numeric results are …
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Electron equations of state during magnetic reconnection
… It is a source of energetic particles in the solar corona and wind, and in planetary magnetospheres. Disruptive reconnection in laboratory fusion experiments rapidly deconfines the plasma. While reconnection alters the global magnetic field and plasma properties, it depends on small-scale …
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The influence of Hall currents, plasma viscosity and electron inertia on magnetic reconnection solutions
This thesis examines magnetic reconnection in the solar corona. Magnetic reconnection is the only mechanism which allows the magnetic topology of magnetized plasmas to be changed. Many of the dynamic processes in the Sun's atmosphere are believed to be driven by magnetic reconnection and studying …
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The origin and dynamic interaction of solar magnetic fields
The dynamics of the solar corona are dominated by the magnetic field which creates its structure. The magnetic field in most of the corona is ?frozen? to the plasma very effectively. The exception is in small localised regions of intense current concentrations where the magnetic field can slip …
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