Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Propagation of seismic waves through a spatio-temporally fluctuating
  medium: Homogenization   Measurements of seismic wave travel times at the photosphere of the Sun have
enabled inferences of its interior structure and dynamics. In interpreting
these measurements, the simplifying assumption that waves propagate through a
temporally stationary medium is almost universally invoked. However, the Sun is
in a constant state of evolution, on a broad range of spatio-temporal scales.
At the zero wavelength limit, i.e., when the wavelength is much shorter than
the scale over which the medium varies, the WKBJ (ray) approximation may be
applied. Here, we address the other asymptotic end of the spectrum, the
infinite wavelength limit, using the technique of homogenization. We apply
homogenization to scenarios where waves are propagating through rapidly varying
media (spatially and temporally), and derive effective models for the media.
One consequence is that a scalar sound speed becomes a tensorial wavespeed in
the effective model and anisotropies can be induced depending on the nature of
the perturbation. The second term in this asymptotic two-scale expansion, the
so-called corrector, contains contributions due to higher-order scattering,
leading to the decoherence of the wavefield. This decoherence may be causally
linked to the observed wave attenuation in the Sun. Although the examples we
consider here consist of periodic arrays of perturbations to the background,
homogenization may be extended to ergodic and stationary random media. This
method may have broad implications for the manner in which we interpret seismic
measurements in the Sun and for modeling the effects of granulation on the
scattering of waves and distortion of normal-mode eigenfunctions.

21
The categories of this paper are: adap-org
3
The categories of this paper are: physics
18
The categories of this paper are: econ
15
The categories of this paper are: nucl-ex
4
The categories of this paper are: cond-mat
25
The categories of this paper are: patt-sol
9
The categories of this paper are: nlin
30
The categories of this paper are: q-alg
19
The categories of this paper are: eess
2
The categories of this paper are: math
7
The categories of this paper are: hep-th
35
The categories of this paper are: mtrl-th
14
The categories of this paper are: math-ph
1
The categories of this paper are: cs
27
The categories of this paper are: comp-gas
10
The categories of this paper are: q-bio