Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Stability of a Spherical Accretion Shock with Nuclear Dissociation   We examine the stability of a standing shock wave within a spherical
accretion flow onto a gravitating star, in the context of core-collapse
supernova explosions. Our focus is on the effect of nuclear dissociation below
the shock on the linear growth, and non-linear saturation, of non-radial
oscillations of the shocked fluid. We combine two-dimensional, time-dependent
hydrodynamic simulations using FLASH2.5 with a solution to the linear
eigenvalue problem, and demonstrate the consistency of the two approaches.
Previous studies of this `Standing Accretion Shock Instability' (SASI) have
focused either on zero-energy accretion flows without nuclear dissociation, or
made use of a detailed finite-temperature nuclear equation of state and
included strong neutrino heating. Our main goal in this and subsequent papers
is to introduce equations of state of increasing complexity, in order to
isolate the various competing effects. In this work we employ an ideal gas
equation of state with a constant rate of nuclear dissociation below the shock,
and do not include neutrino heating. We find that a negative Bernoulli
parameter below the shock significantly lowers the real frequency, growth rate,
and saturation amplitude of the SASI. A decrease in the adiabatic index has
similar effects. The non-linear development of the instability is characterized
by an expansion of the shock driven by turbulent kinetic energy at nearly
constant internal energy. Our results also provide further insight into the
instability mechanism: the rate of growth of a particular mode is fastest when
the radial advection time from the shock to the accretor overlaps with the
period of a standing lateral sound wave. The fastest-growing mode can therefore
be modified by nuclear dissociation.

31
The categories of this paper are: ao-sci
8
The categories of this paper are: hep-ex
19
The categories of this paper are: eess
35
The categories of this paper are: mtrl-th
25
The categories of this paper are: patt-sol
23
The categories of this paper are: solv-int
33
The categories of this paper are: plasm-ph
3
The categories of this paper are: physics
1
The categories of this paper are: cs
32
The categories of this paper are: atom-ph
37
The categories of this paper are: supr-con
12
The categories of this paper are: nucl-th
18
The categories of this paper are: econ
28
The categories of this paper are: alg-geom
4
The categories of this paper are: cond-mat
11
The categories of this paper are: hep-lat