Context Navigation

Update 07/20/2015 - Eddie

4 processes: transmitted shock compresses clump, RT, KH, radiative cooling
- cloud-crushing time: t_{cc} \approx \frac{\sqrt{\chi} ~r_c}{v_s} where \chi is the clump/ambient density ratio, r_c is the clump radius, and v_s is the incident shock velocity
- RT time: t_{RT} \approx \frac{t_{cc}}{\sqrt{kr_c}} , and the dominant mode is of order the clump radius, so the RT instability will grow on time scale equal to t_{cc}
- KH time: t_{KH} \approx \frac{t_{cc}}{kr_c} , and again the dominant mode is of order the clump radius so the KH instability will grow on same time scale t_{cc}
- Radiative cooling is not occurring within the clump because the clump is already very cold (2.5 K) to satisfy pressure equilibrium with the ambient. Even with the transmitted shock, the clump will not reach a temperature large enough to trigger radiative cooling (T > 1000 K).

The simulation time is 75 years, and references state that a clump is typically compressed in 1-2 t_{cc}

Vishniac instability: typically cited for blast waves. Occurs when a slab bounded by a shock and a contact discontinuity is thin enough.

NTSI: usually referred to in colliding flows. A cold slab bounded by two shocks will undergo NTSI if the slab is thin enough.