Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Characterizing the turbulent porosity of stellar-wind structure
  generated by the line-deshadowing instability   We analyze recent 2D simulations of the nonlinear evolution of the
line-deshadowing instability (LDI) in hot-star winds, to quantify how the
associated highly clumped density structure can lead to a "turbulent porosity"
reduction in continuum absorption and/or scattering. The basic method is to
examine the statistical variations of mass column as a function of path length,
and fit these to analytic forms that lead to simple statistical scalings for
the associated mean extinction. A key result is that one can characterize
porosity effects on continuum transport in terms of a single "turbulent
porosity length", found here to scale as $H \approx (f_{\rm cl} - 1) a$, where
$f_{\rm cl} \equiv \left < \rho^2 \right >/\left < \rho \right >^2$ is the
clumping factor in density $\rho$, and $a$ is the density autocorrelation
length. For continuum absorption or scattering in an optically thick layer, we
find the associated effective reduction in opacity scales as $\sim
1/\sqrt{1+\tau_{\rm H}}$, where $\tau_{\rm H} \equiv \kappa \rho H$ is the
local optical thickness of this porosity length. For these LDI simulations, the
inferred porosity lengths are small, only about a couple percent of the stellar
radius, $H \approx 0.02 R_\ast$. For continuum processes like bound-free
absorption of X-rays that are only marginally optically thick throughout the
full stellar wind, this implies $\tau_{\rm H} \ll 1$, and thus that
LDI-generated porosity should have little effect on X-ray transport in such
winds. The formalism developed here could however be important for
understanding the porous regulation of continuum-driven, super-Eddington
outflows from luminous blue variables.

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The categories of this paper are: plasm-ph
3
The categories of this paper are: physics
28
The categories of this paper are: alg-geom
8
The categories of this paper are: hep-ex
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The categories of this paper are: ao-sci
25
The categories of this paper are: patt-sol
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The categories of this paper are: nucl-ex
1
The categories of this paper are: cs
18
The categories of this paper are: econ
14
The categories of this paper are: math-ph
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The categories of this paper are: solv-int
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The categories of this paper are: acc-phys
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The categories of this paper are: supr-con
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The categories of this paper are: atom-ph
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The categories of this paper are: q-alg
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The categories of this paper are: q-bio