TALK ABSTRACT: [PDF available]

The propagation of ring waves across the surface of the sun in response
to a flare initiated sunquake is modeled using Euler's equations of
fluid dynamics.  The solar convection zone is modeled as a plane
parallel gas layer in hydrostatic equilibrium with an adiabatic
temperature gradient.  Small amplitude perturbations about this
equilibrium state are described by the linearized Euler equations for an
inviscid compressible fluid (the actual convective motions on the sun
are neglected for the purpose of calculating the wave motions).  The
normal modes of oscillation of this solar model, which can be expressed
in terms of generalized Laguerre polynomials, are used to construct the
solution of an initial value problem for the linearized equations of
motion.  Assuming that the form of the initial velocity pulse is
Gaussian, the solutions for the vertical velocity at the solar surface
are computed as a function of time and compared to the observational
data for the sunquake event of 9 July 1996.  Model calculations of the
position of the wave packet as a function of time predict arrival times
that are a few minutes ahead of the observations (1 to 5 minutes) for
the range of distances between 10 and 120 Mm from the point of impact
or, equivalently, for the range of times between 15 and 50 minutes after
the assumed time of impact of the flare ejecta (or shock wave) on the
solar surface. It is concluded that the model is in good agreement with
the observational data with an error of roughly 10% or 20%.