Pol Grasland-Mongrain edited The_two_regimes_have.tex  over 8 years ago

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To determine if the thermoelastic or the ablative regime is dominant, we can look at the displacements patterns, which is different between the two regimes \cite{Davies_1993}. As the thermoelastic regime acts mainly as local dipolar forces parallel to the surface, the medium stretches locally parallel to the surface, resulting intwo strong opposite displacements along Y axis (parallel to the surface) and  a weak displacement \textit{outside} the medium along Z axis (normal to the surface). axis, as calculated previously.  In the ablative regime, the point force in the medium displaces the surface \textit{inside} the medium along Zaxis, with weak displacements along Y  axis. Initial displacement along Z axis, as seen at $t$=0.8 ms in Figure \ref{Figure2}, is inside the medium along Z axis; axis%;  moreover, the displacement along Y axis (approx. 1.5 $\mu$m) is quite smaller than the one along Z axis (approx. 3 $\mu$m): $\mu$m)  :  dominant phenomenon is probably the ablative regime. This affirmation is confirmed by the observation of a disk of paler color of the same size as the beam diameter at the impact location of the laser on the phantom, which could correspond to a vaporization of a fraction of the material.