239 research outputs found
Dynamics of volumetrically heated matter passing through the liquid-vapor metastable states
Remaining within the pure hydrodynamic approach, we formulate a
self-consistent model for simulating the dynamic behavior of matter passing
through metastable states in the two-phase liquid-vapor region of the phase
diagram. The model is based on the local criterion of explosive boiling,
derived by applying the theory of homogeneous bubble nucleation in superheated
liquids. Practical application of the proposed model is illustrated with
hydrodynamic simulations of a volumetrically uniformly heated planar layer of
fused silica SiO2. Implications for experimentally measurable quantities are
briefly discussed. A newly developed equation of state, based on the well known
QEOS model and capable of handling homogeneous mixtures of elements, was used
in the numerical simulations.Comment: 14 pages, 9 figure
Creation of a homogeneous plasma column by means of hohlraum radiation for ion-stopping measurements
In this work, we present the results of two-dimensional
radiation-hydrodynamics simulations of a hohlraum target whose outgoing
radiation is used to produce a homogeneously ionized carbon plasma for ion-beam
stopping measurements. The cylindrical hohlraum with gold walls is heated by a
frequency-doubled ( ) long laser pulse
with the total energy of . At the laser spot, the peak matter
and radiation temperatures of, respectively, and are observed. X-rays from the hohlraum heat the attached
carbon foam with a mean density of to a temperature of
. The simulation shows that the carbon ionization degree () and its column density stay relatively stable (within variations
of about ) long enough to conduct the ion-stopping measurements. Also,
it is found that a special attention should be paid to the shock wave, emerging
from the X-ray heated copper support plate, which at later times may
significantly distort the carbon column density traversed by the fast ions.Comment: 12 pages, 12 figure
Coulomb plasmas in outer envelopes of neutron stars
Outer envelopes of neutron stars consist mostly of fully ionized, strongly
coupled Coulomb plasmas characterized by typical densities about 10^4-10^{11}
g/cc and temperatures about 10^4-10^9 K. Many neutron stars possess magnetic
fields about 10^{11}-10^{14} G. Here we briefly review recent theoretical
advances which allow one to calculate thermodynamic functions and electron
transport coefficients for such plasmas with an accuracy required for
theoretical interpretation of observations.Comment: 4 pages, 2 figures, latex2e using cpp2e.cls (included). Proc. PNP-10
Workshop, Greifswald, Germany, 4-9 Sept. 2000. Accepted for publication in
Contrib. Plasma Phys. 41 (2001) no. 2-
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