Title:
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Disentangling chromospheric structure and dynamics through imaging spectroscopy
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This work presents the results of instrumentation developments and scientific studies aimed
at better probing the nature of the solar chromosphere. Indeed, the sources of the energy
and mass to the chromosphere and corona (and the mechanisms by which the energy is
deposited there), remain one of the most mysterious aspects of the structuring of stellar
atmospheres. The goal of this thesis is to apply new methods to studies of the solar
chromosphere in order to advance our understanding of its structure and dynamics.
I perform an analysis of imaging spectroscopy techniques, comparing the spectral fidelity
achieved by different classes of instruments and evaluating a metric for the spectral
measurement efficiency. I describe an upgrade of the Interferometric Bidimensional
Spectrometer (IBIS) to a faster data acquisition system that better allows the application' of
image reconstruction techniques and faster sampling of the rapid variations in the solar
chromosphere.
I use the upgraded system to obtain a unique mosaic providing a comprehensive view of
the chromosphere featuring diffraction-limited resolution, full spectral information, and a
large field of view. I describe two studies that used this dataset to examine the configuration
of the chromospheric magnetic field, revealing that network fields in the upper atmosphere
may be largely non-potential.
I further examine the chromospheric diagnostics provided by several different lines,
exploring the information encoded in chromospheric line widths and combining datasets to
reveal different aspects of the chromospheric conditions. I find that the Ha 6563 and Call
8542 A lines, despite differences in appearances, are largely formed in the same plasma
volumes.
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