Sydney D'Silva
Ph: (703) 346-7306
Helioseismic Tomography
Helioseismic tomography
is a form of the tomographic techniques adapted to image
the interior of the Sun from observations of the acoustic oscillations
at the surface. The important adaptation is the computation of travel
time through time-distance helioseismology. I have contributed in the
aspects of its adaptation and improvement.
eg.
A Note on Helioseismic Tomography
Morphology & Dynamics of Sunspots
This study involves the
dynamics of their progenitors
-- magnetic flux tubes --- from the region
of their origin
(200,000 km beneath the solar surface) through a highly turbulent convectively
unstable region. We modeled the flux tube to be a one-dimensional string
with all properties of a magnetic flux tube allowed to move in the three-dimensional
space of the convection zone. We could successfully explain a number of
dynamical and morphological properties of sunspots if the magnetic
field strength of the flux tubes at the region of their origin were of
the order of 100,000 G. This is order of magnitude larger than the
field that would be in energy equipartition with the turbulent motions.
A Theoretical Model for Tilts of Bipolar Magnetic Regions
Publications in
Solar Physics
and
Biology.
A Few Publications:
(1) Sydney D'Silva, Equivalence between Duvall's Law and the Time-Distance Curve,
The Astrophysical Journal Letters, (2001) 549, L135.
(2) Sydney D'Silva, `Time-Distance Helioseismology at High Frequencies',
The Astrophysical Journal Letters, (2001) 548, L107.
(3) Sydney D'Silva, `A Note on Helioseismic Tomography',
The Astrophysical Journal Letters, (2001) 547 L81.