2,550 research outputs found
The structure of radiative shock waves. III. The model grid for partially ionized hydrogen gas
The grid of the models of radiative shock waves propagating through partially
ionized hydrogen gas with temperature 3000K <= T_1 <= 8000K and density
10^{-12} gm/cm^3 <= \rho_1 <= 10^{-9}gm/cm^3 is computed for shock velocities
20 km/s <= U_1 <= 90 km/s. The fraction of the total energy of the shock wave
irreversibly lost due to radiation flux ranges from 0.3 to 0.8 for 20 km/s <=
U_1 <= 70 km/s. The postshock gas is compressed mostly due to radiative cooling
in the hydrogen recombination zone and final compression ratios are within 1
<\rho_N/\rho_1 \lesssim 10^2, depending mostly on the shock velocity U_1. The
preshock gas temperature affects the shock wave structure due to the
equilibrium ionization of the unperturbed hydrogen gas, since the rates of
postshock relaxation processes are very sensitive to the number density of
hydrogen ions ahead the discontinuous jump. Both the increase of the preshock
gas temperature and the decrease of the preshock gas density lead to lower
postshock compression ratios. The width of the shock wave decreases with
increasing upstream velocity while the postshock gas is still partially ionized
and increases as soon as the hydrogen is fully ionized. All shock wave models
exhibit stronger upstream radiation flux emerging from the preshock outer
boundary in comparison with downstream radiation flux emerging in the opposite
direction from the postshock outer boundary. The difference between these
fluxes depends on the shock velocity and ranges from 1% to 16% for 20 km/s <=
U_1 <= 60 km/s. The monochromatic radiation flux transported in hydrogen lines
significantly exceeds the flux of the background continuum and all shock wave
models demonstrate the hydrogen lines in emission.Comment: 11 pages, 11 figures, LaTeX, to appear in A
- …
