3,509 research outputs found
Model of the tail region of the heliospheric interface
Physical processes in the tail of the solar wind interaction region with the
partially ionized local interstellar medium are investigated in a framework of
the self-consistent kinetic-gas dynamic model. It is shown that the charge
exchange process of the hydrogen atoms with the plasma protons results in
suppression of the gas dynamic instabilities and disappearance the contact
discontinuity at sufficiently (~3000 AU) large distances from the Sun. The
solar wind plasma temperature decreases and, ultimately, the parameters of the
plasma and hydrogen atoms approach to the corresponding parameters of the
unperturbed interstellar medium at large heliocentric distances.Comment: first version, final version is published in Astronomy Letters vol.29
N.1, pp.58-63, 200
The bifurcation phenomena in the resistive state of the narrow superconducting channels
We have investigated the properties of the resistive state of the narrow
superconducting channel of the length L/\xi=10.88 on the basis of the
time-dependent Ginzburg-Landau model. We have demonstrated that the bifurcation
points of the time-dependent Ginzburg-Landau equations cause a number of
singularities of the current-voltage characteristic of the channel. We have
analytically estimated the averaged voltage and the period of the oscillating
solution for the relatively small currents. We have also found the range of
currents where the system possesses the chaotic behavior
Modeling Nonaxisymmetric Bow Shocks: Solution Method and Exact Analytic Solutions
A new solution method is presented for steady-state, momentum-conserving,
non-axisymmetric bow shocks and colliding winds in the thin-shell limit. This
is a generalization of previous formulations to include a density gradient in
the pre-shock ambient medium, as well as anisotropy in the pre-shock wind. For
cases where the wind is unaccelerated, the formalism yields exact, analytic
solutions.
Solutions are presented for two bow shock cases: (1) that due to a star
moving supersonically with respect to an ambient medium with a density gradient
perpendicular to the stellar velocity, and (2) that due to a star with a
misaligned, axisymmetric wind moving in a uniform medium. It is also shown
under quite general circumstances that the total rate of energy thermalization
in the bow shock is independent of the details of the wind asymmetry, including
the orientation of the non-axisymmetric driving wind, provided the wind is
non-accelerating and point-symmetric. A typical feature of the solutions is
that the region near the standoff point is tilted, so that the star does not
lie along the bisector of a parabolic fit to the standoff region. The principal
use of this work is to infer the origin of bow shock asymmetries, whether due
to the wind or ambient medium, or both.Comment: 26 pages and 6 figures accepted to ap
On the effect of transport coefficient anisotropy on the plasma flow in heliospheric interface
The plasma flow in the heliospheric interface is considered. The applicability of hydrodynamic description for this flow is studied. The effect of the magnetic field on the transport properties in the interface plasma is discussed and the dimensionless parameters related to the plasma flow are estimated. It is found that both resistivity and Hall effect can be neglected in Ohm's law, so that the classical induction equation of the ideal magnetohydrodynamic can be used. The Reynolds number is moderately large, so the approximation of inviscid plasma is fairly good. The most important dissipative process is thermal conduction along the magnetic field lines. This effect has to be definitely taken into account. The results obtained in the paper are used to outline the ways for advancing the existing models of the heliospheric interface
Production of Triply Charmed Baryons in Annihilation
The total and differential cross sections for the production of triply
charmed baryons in annihilation are calculated at
the -boson pole.Comment: 13 pages, 2 figure
Magnetic Effects at the Edge of the Solar System: MHD Instabilities, the de Laval nozzle Effect and an Extended Jet
To model the interaction between the solar wind and the interstellar wind,
magnetic fields must be included. Recently Opher et al. 2003 found that, by
including the solar magnetic field in a 3D high resolution simulation using the
University of Michigan BATS-R-US code, a jet-sheet structure forms beyond the
solar wind Termination Shock. Here we present an even higher resolution
three-dimensional case where the jet extends for beyond the Termination
Shock. We discuss the formation of the jet due to a de Laval nozzle effect and
it's su bsequent large period oscillation due to magnetohydrodynamic
instabilities. To verify the source of the instability, we also perform a
simplified two dimensional-geometry magnetohydrodynamic calculation of a plane
fluid jet embedded in a neutral sheet with the profiles taken from our 3D
simulation. We find remarkable agreement with the full three-dimensional
evolution. We compare both simulations and the temporal evolution of the jet
showing that the sinuous mode is the dominant mode that develops into a
velocity-shear-instability with a growth rate of . As a result, the outer edge of the heliosphere
presents remarkable dynamics, such as turbulent flows caused by the motion of
the jet. Further study, e.g., including neutrals and the tilt of the solar
rotation from the magnetic axis, is required before we can definitively address
how this outer boundary behaves. Already, however, we can say that the magnetic
field effects are a major player in this region changing our previous notion of
how the solar system ends.Comment: 24 pages, 13 figures, accepted for publication in Astrophysical
Journal (2004
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