Demonstrating grating-based phase-contrast imaging of laser-driven shock waves

Single-shot X-ray phase-contrast imaging is used to take high-resolution images of laser-driven strong shock waves.Employing a two-grating Talbot interferometer,we successfully acquire standard absorption,differential phase-contrast,and dark-field images of the shocked target.Good agreement is demonstrated between experimental data and the results of two-dimensional radiation hydrodynamics simulations of the laser-plasma interaction.The main sources of image noise are identified through a thorough assessment of the interferometer’s performance.The acquired images demonstrate that grating-based phase-contrast imaging is a powerful diagnostic tool for high-energy-density science.In addition,we make a novel attempt at using the dark-field image as a signal modality of Talbot interferometry to identify the microstructure of a foam target.

Direct imaging of shock wave splitting in diamond at Mbar pressure

Understanding the behavior of matter at extreme pressures of the order of a megabar(Mbar)is essential to gain insight into various physical phenomena at macroscales—the formation of planets,young stars,and the cores of super-Earths,and at microscales—damage to ceramic materials and high-pressure plastic transformation and phase transitions in solids.Under dynamic compression of solids up to Mbar pressures,even a solid with high strength exhibits plastic properties,causing the induced shock wave to split in two:an elastic precursor and a plastic shock wave.This phenomenon is described by theoretical models based on indirect measurements of material response.The advent of x-ray free-electron lasers(XFELs)has made it possible to use their ultrashort pulses for direct observations of the propagation of shock waves in solid materials by the method of phase-contrast radiography.However,there is still a lack of comprehensive data for verification of theoretical models of different solids.Here,we present the results of an experiment in which the evolution of the coupled elastic-plastic wave structure in diamond was directly observed and studied with submicrometer spatial resolution,using the unique capabilities of the x-ray free-electron laser(XFEL).The direct measurements allowed,for the first time,the fitting and validation of the 2D failure model for diamond in the range of several Mbar.Our experimental approach opens new possibilities for the direct verification and construction of equations of state of matter in the ultra-high-stress range,which are relevant to solving a variety of problems in high-energy-density physics.

Acknowledgement to reviewers

In 2020,Matter and Radiation at Extremes(MRE)reached a particularly important milestone when it received its first official impact factor of 2.931,which indicates the high quality of the papers published to date.This outstanding success can be attributed to the strong commitment and valuable contributions from all the reviewers.The Editors of MRE wish to express their deepest gratitude to the following individuals who generously provided advice on manuscripts as reviewers for MRE in the year of 2020.

Matter and radiation at extremes:Prospects and impacts

High-energy-density science(HEDS)has been recognized as a comprehensive new area of physical science,with the potential to revolutionize various scientific and technological fields,including nuclear fusion,particle acceleration,astrophysics,and the properties of condensed matter under extreme conditions.That is why this journal,Matter and Radiation at Extremes(MRE),was established five years ago by the China Academy of Engineering Physics(CAEP)with the mission of informing the worldwide scientific community about progress related to HEDS,whether this be in the basic physics.

Innovative Education and Training in high power laser plasmas(PowerLaPs) for plasma physics, high power laser-matter interactions and high energy density physics-theory and experiments

The Erasmus Plus programme’Innovative Education and Training in high power laser plasmas’,otherwise known as PowerLaPs,is described.The PowerLaPs programme employs an innovative paradigm in that it is a multi-centre programme where teaching takes place in five separate institutes with a range of different aims and styles of delivery.The ’in class’ time is limited to four weeks a year,and the programme spans two years.PowerLaPs aims to train students from across Europe in theoretical,applied and laboratory skills relevant to the pursuit of research in laserplasma interaction physics and inertial confinement fusion(ICF).Lectures are intermingled with laboratory sessions and continuous assessment activities.The programme,which is led by workers from the Technological Educational Institute(TEI)of Crete,and supported by co-workers from the Queen’s University Belfast,the University of Bordeaux,the Czech Technical-University in Prague,Ecole Polytechnique,the University of Ioannina,the University of Salamanca and the University of York,has just completed its first year.Thus far three Learning Teaching Training(LTT)activities have been held,at the Queen’s University Belfast,the University of Bordeaux and the Centre for Plasma Physics and Lasers(CPPL)of TEI Crete.The last of these was a two-week long Intensive Programme(IP),while the activities at the other two universities were each five days in length.Thus far work has concentrated upon training in both theoretical and experimental work in plasma physics,high power laser-matter interactions and high energy density physics.The nature of the programme will be described in detail and some metrics relating to the activities carried out to date will be presented.

Innovative education and training in high power laser plasmas(PowerLaPs) for plasma physics, high power laser matter interactions and high energy density physics: experimental diagnostics and simulations

The second and final year of the Erasmus Plus programme’Innovative Education and Training in high power laser plasmas’,otherwise known as PowerLaPs,is described.The PowerLaPs programme employs an innovative paradigm in that it is a multi-centre programme,where teaching takes place in five separate institutes with a range of different aims and styles of delivery.The’in-class’time is limited to 4 weeks a year,and the programme spans 2 years.PowerLaPs aims to train students from across Europe in theoretical,applied and laboratory skills relevant to the pursuit of research in laser plasma interaction physics and inertial confinement fusion.Lectures are intermingled with laboratory sessions and continuous assessment activities.The programme,which is led by workers from the Hellenic Mediterranean University and supported by co-workers from the Queen’s University Belfast,the University of Bordeaux,the Czech Technical University in Prague,Ecole Polytechnique,the University of Ioannina,the University of Salamanca and the University of York,has just finished its second and final year.Six Learning Teaching Training activities have been held at the Queen’s University Belfast,the University of Bordeaux,the Czech Technical University,the University of Salamanca and the Institute of Plasma Physics and Lasers of the Hellenic Mediterranean University.The last of these institutes hosted two 2-week-long Intensive Programmes,while the activities at the other four universities were each 5 days in length.In addition,a’Multiplier Event’was held at the University of Ioannina,which will be briefly described.In this second year,the work has concentrated on training in both experimental diagnostics and simulation techniques appropriate to the study of plasma physics,high power laser matter interactions and high energy density physics.The nature of the programme will be described in detail,and some metrics relating to the activities carried out will be presented.In particular,this paper will focus on the overall assessment of the programme.