Hae Ja Lee

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Ultrafast X-ray Studies on Dynamics of Matter in Extreme Conditions

Dr. Hae Ja Lee, SLAC, Stanford University

Investigation of matter properties in extreme thermodynamic conditions has attracted numerous experimental and theoretical work motivated by its implication in shock wave physics, high pressure physic, geoscience, dense plasmas, warm dense matter, x-ray and laser created plasmas, and astrophysically relevant plasmas. Static compression studies using diamond anvil cells and synchrotron light source have revealed structural phase transitions of crystalline material under high pressure. Recent shock compression studies at high power optical laser facilities have accomplished measurements of material properties in extreme conditions beyond pressures generated by diamond anvil cells. In particular, dynamic compression experiments have contributed to produce and probe a broad range of extreme conditions on very short time scales. However, the understanding the atomic-level dynamic response of material under such conditions are not well understood yet.

The LCLS free electron laser providing femtosecond pulses of keV x-rays with sufficient brilliance (~1012 photons /pulse) is well suited to examine dynamic responses in materials subject to a broad range of peak stresses (~ 5 GPa to above 100 GPa) and time durations (10s fs up to several hundred ns). Development of advanced diagnostic technique using LCLS beam permits experiments in the regimes of interest at the time and spatial scales of the simulations. This talk will present state-of-the-art experimental platform at MEC endstation and address phase transitions and dynamic responses of several materials including Bi, Si, SiO2 during shock loading. I will also look into the potential to advance our knowledge of the dynamic behavior.