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• Explosive melting and evaporation of solids

• Metals (with significant melt phase) undergo phase explosion upon high energy irradiation

• Classical Sedov-Taylor point source explosion theory seems to work here

• Hydrodynamic modeling of Laser explosion

• Ignition of energetic matter (space propulsion and weapons) via laser

The Sequent shock wave images of Aluminum and Copper by 20mJ/pulse laser incident intensities shown in the increasing order

of time elapse(30, 50, 70, 90, 120, 160, 200, 300, 400ns).

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1041mm thick metal (Eo=200mJ)

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• Images at two different instances (22 ns apart), suggesting shock velocity of 4500 m/s

• This says that early-on profiles are given by the solution of Euler equations for metal vapor-air shock interaction

• Theoretical Hugoniotproperties of laser induced shock state during the first 1000 ns of 20 mJ/pulse beam.

• Shock speed is measured (~4500 m/s), other variables are estimated from strong shock approximation

• Calculations show the shocked states behind the initial planar explosive wave at 75ns is reproduced

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Parameter & Property Acetylene-air mixture Ethylene-air mixtureInitial pressure (P0) 1.33 104Pa 1.33 104Pa

Initial temperature (T0) 293K 293KInitial density (ρ0) 1.58 10-1kg/m3 1.58 10-1kg/m3

Specific heat rate (γ) 1.25 1.15Molecular weight (M) 29 10-3kg/mol 29 10-3kg/mol

Pre-exponential factor (A) 1 109m3/(kg s) 3.2 108m3/(kg s)Activation energy (Ea) 29.3RT0 35.3514RT0

Chemical energy release (q) 35.0RT0/M 48.824RT0/MTransport constants (ν0=μ0=D0) 1.3 10-7kg/(s m K0.7) 7.0 10-8kg/(s m K0.7)Adiabatic flame temperature 2340K 2625K

Adiabatic flame density 1.98 10-2kg/m3 1.77 10-2kg/m3

Incident shock intensity 1.2 1.9

25

• Schematic of initial setup

[T. Scarinci, etc., 1993]

FlameIncident shock

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[G. Thomas, etc., 2001]

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