ISSN:
1089-7674
Source:
AIP Digital Archive
Topics:
Physics
Notes:
The linear growth rate of the Rayleigh–Taylor instability is calculated for accelerated ablation fronts with small Froude numbers (Fr(very-much-less-than)1). The derivation is carried out self-consistently by including the effects of finite thermal conductivity (κ∼Tν) and density gradient scale length (L). It is shown that long-wavelength modes with wave numbers kL0(very-much-less-than)1 [L0=νν/(ν+1)ν+1 min(L)] have a growth rate γ(approximately-equal-to)(square root of)ATkg−βkVa, where Va is the ablation velocity, g is the acceleration, AT=1+O[(kL0)1/ν], and 1〈β(ν)〈2. Short-wavelength modes are stabilized by ablative convection, finite density gradient, and thermal smoothing. The growth rate is γ=(square root of)αg/L0+c20k4L20V2a−c0k2L0Va for 1(very-much-less-than)kL0(very-much-less-than)Fr−1/3, and γ=c1g/(Vak2L20)−c2kVa for the wave numbers near the cutoff kc. The parameters α and c0−2 mainly depend on the power index ν; and the cutoff kc of the unstable spectrum occurs for kcL0∼Fr−1/3(very-much-greater-than)1. Furthermore, an asymptotic formula reproducing the growth rate at small and large Froude numbers is derived and compared with numerical results. © 1996 American Institute of Physics.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1063/1.872078
