dc.description.abstract |
Corona, the outermost layer of the solar atmosphere, is made up with very hot and
taneous plasma material. The density and temperature structuring of this layer, is
largely inhomogenous. Temperatures, at certain locations, can reach upto tens of
million kelvin (MK). One of the key questions regarding the coronal physics is to
identify the ubiquitous source(s) which can sustain this high temperature profile of
the coronal plasma. One of the potential candidates in this case, is the family of
magnetohydrodynamic (MHD) waves. These waves can propagate from the lower
atmosphere to the solar corona and can partially (or fully) dissipate their energy to
the surrounding coronal medium. In fact, different physical parameters such as the
density, magnetic field and temperature of the host structure can also be inferred by
studying the different properties of the propagating MHD wave.
This thesis is focused on examining the different properties of solar magnetohydro-
dynamic (MHD) waves, specifically the slow magnetoacoustic mode (also known as
‘slow wave’), as seen with modern high resolution space based telescopes. Three key
aspects: Generation, Propagation and Damping of these waves are studied rigorously
in this thesis. A combination of high resolution spectroscopic and imaging data from
the ‘Extreme-ultraviolet Imaging Spectrometer’, onboard Hinode and ‘Atmospheric
Imaging Assembly’ (AIA), onboard Solar Dynamics Observatory (SDO), are used for
the unambiguous detection of slow waves. Data from the ‘Helioseismic and Magnetic
Imager’ (HMI) onboard SDO, and the ‘X-Ray Telescope’ (XRT) onboard Hinode, are
also used to study the generation of these waves. Apart from the generation, we also
study the damping of these waves while they propagate through large coronal struc-
tures, such as active region loops, polar plumes-interplumes etc. A large volume of
AIA imaging data have been analyzed to statistically determine the various properties
of the damping mechanisms. To supplement the observed results, we performed 3-
D numerical simulations, along with the advanced ‘forward modelling’ technique and
explained the observed wave properties. |
en_US |