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First HED experiment at XFEL

Professor Justin Wark

Professor of Physics

Sub department

  • Atomic and Laser Physics

Research groups

  • Oxford Centre for High Energy Density Science (OxCHEDS)
Justin.Wark@physics.ox.ac.uk
Telephone: 01865 (2)72251
Clarendon Laboratory, room 029.9
  • About
  • Publications

Shock compression experiments using the DiPOLE 100-X laser on the high energy density instrument at the European x-ray free electron laser: quantitative structural analysis of liquid Sn

Journal of Applied Physics AIP Publishing 135:16 (2024) 165902

Authors:

Mg Gorman, D McGonegle, Rf Smith, S Singh, T Jenkins, Rs McWilliams, B Albertazzi, Sj Ali, L Antonelli, Mr Armstrong, C Baehtz, Ob Ball, S Banerjee, Ab Belonoshko, A Benuzzi-Mounaix, Ca Bolme, V Bouffetier, R Briggs, K Buakor, T Butcher, S Di Dio Cafiso, V Cerantola, J Chantel, A Di Cicco, S Clarke, Al Coleman, J Collier, Gw Collins, Aj Comley, F Coppari, Te Cowan, G Cristoforetti, H Cynn, A Descamps, F Dorchies, Mj Duff, A Dwivedi, C Edwards, Jh Eggert, D Errandonea, G Fiquet, E Galtier, A Laso Garcia, H Ginestet, L Gizzi, A Gleason, S Goede, Jm Gonzalez, M Harmand, Nj Hartley

Abstract:

X-ray free electron laser (XFEL) sources coupled to high-power laser systems offer an avenue to study the structural dynamics of materials at extreme pressures and temperatures. The recent commissioning of the DiPOLE 100-X laser on the high energy density (HED) instrument at the European XFEL represents the state-of-the-art in combining x-ray diffraction with laser compression, allowing for compressed materials to be probed in unprecedented detail. Here, we report quantitative structural measurements of molten Sn compressed to 85(5) GPa and ∼ 3500 K. The capabilities of the HED instrument enable liquid density measurements with an uncertainty of ∼ 1 % at conditions which are extremely challenging to reach via static compression methods. We discuss best practices for conducting liquid diffraction dynamic compression experiments and the necessary intensity corrections which allow for accurate quantitative analysis. We also provide a polyimide ablation pressure vs input laser energy for the DiPOLE 100-X drive laser which will serve future users of the HED instrument.
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Dielectronic satellite emission from a solid-density Mg plasma: relationship to models of ionisation potential depression

Physical Review E American Physical Society 109:4 (2024) 045204

Authors:

Gabriel Pérez-Callejo, Thomas Gawne, TR Preston, Patrick Hollebon, Sam Vinko, Steven Rose, Justin Wark

Abstract:

We report on experiments where solid-density Mg plasmas are created by heating with the focused output of the Linac Coherent Light Source x-ray free-electron laser. We study the K-shell emission from the helium- and lithium-like ions using Bragg crystal spectroscopy. Observation of the dielectronic satellites in lithium-like ions confirms that the M-shell electrons appear bound for these high charge states. An analysis of the intensity of these satellites indicates that when modeled with an atomic-kinetics code, the ionization potential depression model employed needs to produce depressions for these ions which lie between those predicted by the well known Stewart-Pyatt and Ecker-Kroll models. These results are largely consistent with recent density functional theory calculations.
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Phase transitions of Fe$_2$O$_3$ under laser shock compression

(2024)

Authors:

A Amouretti, C Crépisson, S Azadi, D Cabaret, T Campbell, DA Chin, B Colin, GR Collins, L Crandall, G Fiquet, A Forte, T Gawne, F Guyot, P Heighway, H Lee, D McGonegle, B Nagler, J Pintor, D Polsin, G Rousse, Y Shi, E Smith, JS Wark, SM Vinko, M Harmand
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Quantifying ionization in hot dense plasmas

Physical Review E American Physical Society 109 (2024) L023201

Authors:

Thomas Gawne, Sam Vinko, Justin Wark

Abstract:

Ionization is a problematic quantity in that it does not have a well-defined thermodynamic definition, yet it is a key parameter within plasma modelling. One still therefore aims to find a consistent and unambiguous definition for the ionization state. Within this context we present finite-temperature density functional theory calculations of the ionization state of carbon in CH plasmas using two potential definitions: one based on counting the number of continuum electrons, and another based on the optical conductivity. Differences of up to 10% are observed between the two methods. However, including “Pauli forbidden” transitions in the conductivity reproduces the counting definition, suggesting such transitions are important to evaluate the ionization state.
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Achievement of target gain larger than unity in an inertial fusion experiment

Physical Review Letters American Physical Society 132:6 (2024) 065102

Authors:

H Abu-Shawareb, R Acree, P Adams, J Adams, B Addis, R Aden, P Adrian, Bb Afeyan, M Aggleton, L Aghaian, A Aguirre, D Aikens, J Akre, F Albert, M Albrecht, Bj Albright, J Albritton, J Alcala, C Alday, Da Alessi, N Alexander, J Alfonso, N Alfonso, E Alger, Sj Ali, Za Ali, A Allen, We Alley, P Amala, Pa Amendt, P Amick, S Ammula, C Amorin, Dj Ampleford, Rw Anderson, T Anklam, N Antipa, B Appelbe, C Aracne-Ruddle, E Araya, Tn Archuleta, M Arend, P Arnold, T Arnold, A Arsenlis, J Asay, Lj Atherton, D Atkinson, R Atkinson, Jm Auerbach

Abstract:

On December 5, 2022, an indirect drive fusion implosion on the National Ignition Facility (NIF) achieved a target gain G_{target} of 1.5. This is the first laboratory demonstration of exceeding "scientific breakeven" (or G_{target}>1) where 2.05 MJ of 351 nm laser light produced 3.1 MJ of total fusion yield, a result which significantly exceeds the Lawson criterion for fusion ignition as reported in a previous NIF implosion [H. Abu-Shawareb et al. (Indirect Drive ICF Collaboration), Phys. Rev. Lett. 129, 075001 (2022)PRLTAO0031-900710.1103/PhysRevLett.129.075001]. This achievement is the culmination of more than five decades of research and gives proof that laboratory fusion, based on fundamental physics principles, is possible. This Letter reports on the target, laser, design, and experimental advancements that led to this result.
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