Laboratory experiments can address certain issues relevant to astrophysical objects and improve our understanding of physical processes that occur in remote regions of the universe. The new laser facilities and diagnostic technologies allow astrophysical models and large scale simulation techniques to be tested under relevant conditions. Two mains topics have been studied at CELIA.
Supersonic radiative and multi-material plasma jet production
Two experimental campaigns have been performed on the PALS laser that allowed studying the jet production using a single laser beam, to characterize interaction of these jets with an ambient medium and last to modify the jet structure by adding various materials in the jet body. The structures observed in our
experiments are qualitatively very similar to those seen in astrophysical objects on completely different time and space scales. Our analysis shows that several parameters and dimensionless parameters have values close to those seen in young stellar objects like the velocity, the Mach number, the jet-plasma density ratio and the dissipative processes described by the cooling parameter. The observed structures are reproduced with a two dimensional radiation hydrodynamic code.
Supernovae remnants and hydrodynamic instabilities
The Rayleigh Taylor instability (RTI) plays a key role in the dynamics of supernova remnants (SNR). The compressibility effects have been studied for both static and non stationary configurations related to the late stage of SNR evolution. By using a specific time dependent transformation, a dispersion relation has been derived for a non stationary background flow. This expanding shell model is applied for studies of plerions (young type II SNR), the disruptions and fragmentations of the dense shell surrounding the central pulsar. The general analysis is applied to the Crab Nebula.