In the last newsletter published by the Orion laser team, F. Suzuki-Vidal discusses his work on radiative shocks and mentions his presentation at PLAS@PAR scientific day on January 22, 2016.
 

 

An extract of the newsletter is available here, courtesy of the ORION laser team:

One of the academic access experiments hosted by ORION in 2015 looked at the interaction between counter-streaming radiative shocks inside miniature gas-filled targets, as part of an ongoing effort to study astrophysical phenomena in the laboratory, a field known as ‘laboratory plasma astrophysics’. The project was led by researchers from the Plasma Physics group at Imperial College London in collaboration with international researchers from France, Spain and Czech Republic.

The experiments, which finished in October 2015, were considered a success by the members of the scientific team. The results proved the reliability of some of the diagnostics on Orion, such as point-projection X-ray backlighting. The figure shows, from left to right, an actual view of one of the octagonal gas-filled targets used in the experiments (developed by RAL/Scitech) together with results from X-ray backlighting taken through one of the side-on viewing windows of the target. The image shows the interaction between two counter-propagating shocks in Xenon at an initial pressure of ~1/3 atm, 35ns after the Orion long-pulse beams drove the shocks through the gas. At this time the two shocks have already collided, forming a complex feature at the centre of the window. In addition, the experiments served as a platform for fielding and testing new diagnostics on Orion such as 2-D, multi-frame optical interferometry, which will allow characterising the spatial distribution of electron density ahead of the shocks.

The project PI, Francisco Suzuki-Vidal, described working alongside Orion staff as a unique and highly gratifying experience, as overall it provided with a platform for academics to access world class, state-of-the art laser facilities and plasma diagnostics which are not easily available otherwise.

Although the data is currently under analysis, some preliminary results have already been presented to members of the plasma physics community, for instance at the recent High-Power Laser Meeting in Abingdon, UK, and during the PLAS@PAR Scientific Day at Universite Pierre et Marie Curie in Paris. The aim now is to present the results to the international scientific community at the High-Energy Density Laboratory Astrophysics (HEDLA) conference to be held in the US in May.

 

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Left: Actual image of one of the octagonal gas-filled targets to produce counter-streaming radiative shocks.

Right: X-ray backlighting results at 35 ns showing two counter-propagating shocks interacting at the centre of the window.