Proton Imaging of Laser-Produced Plasmas

Fusion CDT students returned to Orion for two more weeks in November 2015, along with a team of visiting PhD students from the University of York, Queen’s University of Belfast, Imperial College and University of Michigan.

The experiment was to continue a study of the growth and movement of intense self-generated magnetic fields and reconnection events in plasmas created as powerful lasers focus on to a target. Reconnection is a fundamental and poorly understood process that occurs in space and terrestrial plasmas and results in releases of magnetic energy. The experiments on Orion represent a new regime that is only accessible on a handful of systems around the world.

Ellie Tubman, a fourth year Fusion CDT student led the experiment. Ellie said: “From the first shot we got data just like we did in February. This time the data is very high quality. We also ran more diagnostics including optical interferometry and X-ray spectroscopy as well as the proton and X-ray pinhole imaging used last time. It was really enjoyable; the staff are great. They are a good bunch to work with; friendly, helpful and supportive. It would not have been possible to run an experiment like this, using complex targets and so many diagnostics, without this help and support. Thank you Orion”.

“We also worked with the Target Fabrication team at the Central Laser Facility. They did such an amazing job producing our targets and they were willing to adapt these complex ‘creations’ as the experiment developed.”

Sarah Wilson is also a Fusion CDT student and is in her second year. This was Sarah’s first experiment at Orion and she added ‘Orion is an impressive facility and I agree it was a pleasure to work with the Orion team. Working here is quite different as we need to define the experiment parameters before the shot and get someone else to do it. It is very hands-off! Yet, we got to visit the target area and go into the chamber. As I did much of the target metrology seeing the target chamber from the inside was really fantastic and considerably helped my understanding of TIMs (target diagnostic insertion devices) and TVS (Target Viewing System) positions.”

Phil Durey (Fusion CDT third year student) also attended and worked with the other students to provide on-site and on the fly data interpretation. Phil said “having my laptop and internet connection allowed me to do some initial analysis of the data. This is a great start and brings a helpful focus for when we go home”.

Ellie ended “I look forward to continuing to work with colleagues at AWE/Orion as we learn to interpret this data and continue to coordinate the project with the Imperial College, Michigan, Queen’s and York team.”

Following the experiment, the team has been busy interpreting the results ready for discussion at various meetings. In December Ellie and team presented their work at the 2015 Christmas Meeting of the High Power Laser Community in Abingdon near Oxford and again at the 2016 National Ignition Facility & Jupiter Laser Facility User Group Meeting near San Francisco, California.