Presentasjon av masteroppgave: Asbjørn Lie Parmer
Imaging the Solar Chromosphere with the Atacama Large Millimeter/submillimeter Array
The chromosphere is nearly translucent in the optical and infrared continuum, making
it an elusive observational target. In this thesis, I use a CO5BOLD computational 3D
radiation magnetohydrodynamics (MHD) model of the solar atmosphere to investigate
what the chromosphere might look like with the newly built Atacama Large Millimeter/
submillimeter Array (ALMA).
The radiative transport solver LINFOR3D is used to produce synthetic brightness temperature
maps of the MHD model at several wavelengths in the (sub-)mm range, and the
maps are analyzed and compared with the MHD model to discern the relation between
observing wavelength and the formation height of the radiation. The software package
CASA is then used to simulate interferometric ALMA observations of the brightness
temperature maps. We investigate the capabilities of the method clean to produce
images from the simulated ALMA observations.
The radiative transfer calulations on the MHD model indicate that possible probing
depth of ALMA observations extend from the upper photosphere at the wavelength
= 0:3 mm, to the middle chromosphere at = 8:6 mm. The ALMA observations
resolves the chromospheric structure to an extent that facilitates imaging with a spatial
resolution of up to 0.3 arcseconds at = 1 mm. This is close to the resolution of current
optical telescopes, and may result in revolutionizing new data about the chromosphere.
Veileder: Forsker Sven Wedemeyer-Böhm, Institutt for teoretisk astrofysikk, UiO
Intern sensor: Førsteamanuensis Boris Vilhelm Gudiksen, Institutt for teoretisk astrofysikk, UiO
Ekstern sensor: Dr. Hans-Günter Ludwig, Department of Physics and Astronomy, University of Heidelberg, Germany