192 / 2023-04-15 17:13:27

Dynamic compression driven by surface return current in relativistic laser cryogenic hydrogen jets interactions

极端光下的基础物理学 > 基础物理-II

An extremely strong transient current with density in the order of ~ 1e17A/m² is generated along the surface of a micron-size solid target irradiated by a femtosecond relativistic laser pulse that can be utilized as a driving source for the dynamic high-pressure experiments, in alternative to the large-scale conventional Z-pinch and nanoseconds long pulse laser methodology. In this study, we investigate the dynamic compression driven by the surface return current in the relativistic laser cryogenic hydrogen jets interactions by Particle-in-Cell (PIC) and hydrodynamic simulations. Our results reveal two competition mechanisms of the dynamic compression initialized by the surface current in this scenario: magnetic pressure compression driven by a few tens of Kilotesla magnetic field at early phase and thermal compression driven by the surface ablation plasma. The simulations show that the density of cryogenic hydrogen jets is compressed with a factor of ~3-10 and the thermal pressure reaches terapascal (TPa) scale. The experimental signal of dynamic compression in the cryogenic hydrogen jets performed at HZDR DRACO PW laser facility will be also presented.  Our research shows the underlying mechanism of return current compression in short laser-solid interactions, presenting a novel platform for investigating dynamic compression in warm and hot dense matter.