Speaker
Jaroslav Triaskin
Description
See the full Abstract at http://ocs.ciemat.es/EPS2018ABS/pdf/P4.3003.pdf
Impact of shock wave on weakly ionized gas: numerical evaluation
V.A. Pavlov1 , J.V. Triaskin1
1 Physics Department, St. Petersburg State University, 1, Ulyanovskaya str., Petrodvorets,
198504, St. Petersburg, Russia
The basic principles of nonlinear ion-acoustic waves formation in weakly ionized gas sub-
jected to the shock wave of neutral gas were investigated by the numerical and analytical
methods. The ion-acoustic approximation were employed to describe the plasma component
of charged gas [1]. Within a such approach the ion-acoustic waves arise via the collisions of
charges with the neutral particles only. For numerical simulation the initial and approximate
boundary conditions for non-stationary problem are determined in assumption that the solution
of runaway wave type can be found [2]. The strong anomalous nonlinear effects appear in this
case. The competitive action of nonlinearity, dispersion and dissipation at the formation of spe-
cific plasma "condensations" and "rarefactions" is shown [2]. In narrow range of the shock wave
velocities the anomalous relaxation of plasma oscillations occurs behind the front. It appears in
the total ambipolar entrainment by the shock wave of charged components. This effect possibly
results from the strong nonlinear resonant (in respect to the shock wave velocity) perturbation
in the region ahead of front.
Nonlinear perturbations of weakly ionized non-isothermal gas (Te Ti ≈ Tn ) under the ac-
tion of a strong stationary shock wave of the neutral component have been studied based on
computer-aided calculations. The detected patterns reflect the most essential features of the
additional mechanism of reduction of the intensity of a strong shock wave of the neutral com-
ponent without energy release for heating the region ahead of the front. The reciprocal action of
the charged components upon the neutral particles result in change of the structure and reduction
of the intensity of the shock wave. In such a case, a paradoxical situation arises: low-ionized
plasma (the nonperturbed state is meant) exerts a strong effect upon the neutral component
and the reduction of the shock wave intensity. Laboratory experiment data to corroborate such
influence are available [3].
References
[1] V. A. Pavlov, Plasma Phys. Rep. 22, 167, (1996)
[2] V.A. Pavlov. Ya. V. Tryaskin. Journal of Applied Mechanics and Technical Physics, Vol. 56, No. 3, (2015)
[3] Yu. L. Serov, MODERN SCIENCE, No.2, Vol.10, 2012
