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| 1 | Evolution of X-pinch loads for pulsed power generators with current from 50 to 5000 kA显示文摘A review of X-pinches of various configurations and of different materials as an X-ray source for various applications is presented. Theadvantages and disadvantages of different designs of X-pinches as a load for generators with a wide range of output parameters and as a sourceof X-ray radiation for X-ray point-projection imaging were analyzed. | T.A.Shelkovenko S.A.Pikuz I.N.Tilikin M.D.Mitchell S.N.Bland D.A.Hammer | 2018 | Matter and Radiation at Extremes2018，3，6： | 2 |
| 2 | A portable X-pinch design for x-ray diagnostics of warm dense matter显示文摘We describe the design and x-ray emission properties(temporal,spatial,and spectral)of Dry Pinch I,a portable X-pinch driver developed at Imperial College London.Dry Pinch I is a direct capacitor discharge device,30033003700 mm3 in size and∼50 kg in mass,that can be used as an external driver for x-ray diagnostics in high-energy-density physics experiments.Among key findings,the device is shown to reliably produce 1.1±0.3 ns long x-ray bursts that couple∼50 mJ of energy into photon energies from 1 to 10 keV.The average shot-to-shot jitter of these bursts is found to be 10±4.6 ns using a combination of x-ray and current diagnostics.The spatial extent of the x-ray hot spot from which the radiation emanates agrees with previously published results for X-pinches-suggesting a spot size of 10±6μm in the soft energy region(1–10 keV)and 190±100μm in the hard energy region(>10 keV).These characteristics mean that Dry Pinch I is ideally suited for use as a probe in experiments driven in the laboratory or at external facilities when more conventional sources of probing radiation are not available.At the same time,this is also the first detailed investigation of an X-pinch operating reliably at current rise rates of less than 1 kA/ns. | J.Strucka J.W.D.Halliday T.Gheorghiu H.Horton B.Krawczyk P.Moloney S.Parker G.Rowland N.Schwartz S.Stanislaus S.Theocharous C.Wilson Z.Zhao T.A.Shelkovenko S.A.Pikuz S.N.Bland | 2022 | Matter and Radiation at Extremes2022，7，1： | 0 |
| 3 | Characterization of hot electrons generated by laser-plasma interaction at shock ignition intensities显示文摘In an experiment carried out at the Prague Asterix Laser System at laser intensities relevant to shock ignition conditions(I>10^(16) W/cm^(2)),the heating and transport of hot electrons were studied by using several complementary diagnostics,i.e.,K_(α)time-resolved imaging,hard x-ray filtering(a bremsstrahlung cannon),and electron spectroscopy.Ablators with differing composition from low Z(parylene N)to high Z(nickel)were used in multilayer planar targets to produce plasmas with different coronal temperature and collisionality and modify the conditions of hot-electron generation.The variety of available diagnostics allowed full characterization of the population of hot electrons,retrieving their conversion efficiency,time generation and duration,temperature,and angular divergence.The obtained results are shown to be consistent with those from detailed simulations and similar inertial confinement fusion experiments.Based on the measured data,the advantages,reliability,and complementarity of the experimental diagnostics are discussed. | E.D.Filippov M.Khan A.Tentori P.Gajdos A.S.Martynenko R.Dudzak P.Koester G.Zeraouli D.Mancelli F.Baffigi L.A.Gizzi S.A.Pikuz Ph.D.Nicolaï N.C.Woolsey R.Fedosejevs M.Krus L.Juha D.Batani O.Renner G.Cristoforetti | 2023 | Matter and Radiation at Extremes2023，8，6： | 0 |
| 4 | Precise wavelength measurements of potassium He- and Li-like satellites emitted from the laser plasma of a mineral target显示文摘Atomic models of high-Zmulticharged ions are extremely complex and require experimental validation.Oneway to do so is to crosscheck the predicted wavelengths of resonance transitions in He-and Li-like ions against precise spectroscopic measurements that use the spectral lines of H-like ions for spectra calibration;these reference data can be modeled with outstanding precision.However,for elements with Z of at least 15,it is quite difficult to create a hot dense plasma with a large concentration ofH-like charge states.To mitigate this issue,the suggestion here is to use as laser targets particular minerals comprising elements with moderate(between 15 and 30)and low(less than 15)Z,with emission from the latter delivering perfect reference lines over a whole range o fHe-and Li-like moderate-Z emission under examination.This approach is implemented to measure the wavelengths of resonance transitions(1snp→1s^(2) for n=2,3)in He-likeKions and their dielectronic satellites by irradiating plates of orthoclase(KAlSi_(3)O_(8))with0.5-kJ subnanosecond laser pulses.X-ray spectra of the laser-generated plasma contain the investigated lines of highly charged K-ions together with precisely known reference lines of H-like Al and Si atoms.The K-shell spectral line wavelengths are measured with a precision of around 0.3 mA. | S.N.Ryazantsev I.Yu.Skobelev E.D.Filippov A.S.Martynenko M.D.Mishchenko M.Krus O.Renner S.A.Pikuz | 2021 | Matter and Radiation at Extremes2021，6，1： | 0 |
| 5 | Optimization of a laser plasma-based x-ray source according to WDM absorption spectroscopy requirements显示文摘X-ray absorption spectroscopy is a well-accepted diagnostic for experimental studies of warm dense matter.It requires a short-lived X-ray source of sufficiently high emissivity and without characteristic lines in the spectral range of interest.In the present work,we discuss how to choose an optimum material and thickness to get a bright source in the wavelength range 2A–6A(∼2 keV to 6 keV)by considering relatively low-Z elements.We demonstrate that the highest emissivity of solid aluminum and silicon foil targets irradiated with a 1-ps high-contrast sub-kJ laser pulse is achieved when the target thickness is close to 10μm.An outer plastic layer can increase the emissivity even further. | A.S.Martynenko S.A.Pikuz I.Yu.Skobelev S.N.Ryazantsev C.D.Baird N.Booth L.N.K.Dohl P.Durey A.Ya.Faenov D.Farley R.Kodama K.Lancaster P.McKenna C.D.Murphy C.Spindloe T.A.Pikuz N.Woolsey | 2021 | Matter and Radiation at Extremes2021，6，1： | 0 |
| 6 | Core structure and secondary breakdown of an exploding wire in the current-pause regime显示文摘The results of experiments with rapidly exploding thin conductors inthe current-pause regime are presented.Copper wires 25mmin diameter and 12 mm in length serve as loads for a GVP pulsed generator based on a low-inductance capacitor.The generator produces current pulses of up to 10 kA with dI/dt up to 50 A/ns.A 100–800-ns current-pause regime is obtained for charging voltages of 10–15 kV.The discharge channel structure is studied by shadow photography using 0.53-mm,10-ns second-harmonic pulses from aNd31:YAG laser.In the experiments,three types of secondary breakdown are observed,with different symmetry types,different current-pause durations,and different dependences on the energy deposited into the wire during its resistive heating.All of these breakdown types develop inside a tubular core that is produced in the current-pause stage and that remains almost undamaged by the breakdown. | V.M.Romanova A.R.Mingaleev A.E.Ter-Oganesyan T.A.Shelkovenko G.V.Ivanenkov S.A.Pikuz | 2019 | Matter and Radiation at Extremes2019，4，2： | 0 |
| 7 | X-ray spectroscopy evidence for plasma shell formation in experiments modeling accretion columns in young stars显示文摘Recent achievements in laboratory astrophysics experiments with high-power lasers have allowed progress in our understanding of the early stages of star formation.In particular,we have recently demonstrated the possibility of simulating in the laboratory the process of the accretion of matter on young stars[G.Revet et al.,Sci.Adv.3,e1700982(2017)].The present paper focuses on x-ray spectroscopy methods that allow us to investigate the complex plasma hydrodynamics involved in such experiments.We demonstrate that we can infer the formation of a plasma shell,surrounding the accretion column at the location of impact with the stellar surface,and thus resolve the present discrepancies between mass accretion rates derived from x-ray and optical-radiation astronomical observations originating from the same object.In our experiments,the accretion column ismodeled by having a collimated narrow(1 mm diameter)plasma stream first propagate along the lines of a large-scale external magnetic field and then impact onto an obstacle,mimicking the high-density region of the stellar chromosphere.A combined approach using steady-state and quasi-stationarymodels was successfully applied tomeasure the parameters of the plasma all along its propagation,at the impact site,and in the structure surrounding the impact region.The formation of a hot plasma shell,surrounding the denser and colder core,formed by the incoming stream of matter is observed near the obstacle using x-ray spatially resolved spectroscopy. | E.D.Filippov I.Yu.Skobelev G.Revet S.N.Chen B.Khiar A.Ciardi D.Khaghani D.P.Higginson S.A.Pikuz J.Fuchs | 2019 | Matter and Radiation at Extremes2019，4，6： | 0 |
| 8 | Explosion dynamics of thin flat foils at high current density显示文摘This paper presents characteristic features of the explosion of thin flat foils for currents and pulse risetimes ranging from 8 kA at 350 ns to1000 kA at ∼100 ns. Foils made of aluminum, copper, nickel, and titanium with thicknesses of 1–100 μm are tested. Various diagnostics inthe optical, UV, and x-ray spectral ranges are used to image the exploding foils from initial breakdown to complete destruction or pinching.It is shown that foil explosion is a complex process that depends on many factors, but features common to all foils are found that do notdepend on the parameters of the generators or, accordingly, on the energy deposited in the foil: for example, the breakdown of flat foils underdifferent conditions occurs at the edges of the foil. For the first time, the formation of a precursor over the central part of the foil is shown,which significantly changes the dynamics of the foil explosion. | T.A.Shelkovenko I.N.Tilikin S.A.Pikuz A.R.Mingaleev V.M.Romanova L.Atoyan D.A.Hammer | 2022 | Matter and Radiation at Extremes2022，7，5： | 0 |
| 9 | Methods of controlled formation of instabilities during the electrical explosion of thin foils显示文摘The results of a study of the electrical explosion of aluminum foils with an artificial periodic surface structure created by laser engraving are presented.Experiments were carried out on pulsed high-current generators BIN(270 kA,300 kV,100 ns)and KING(200 kA,40 kV,200 ns)with Al foil of thicknesses 16 and 4μm,respectively.Images of the exploded foils were recorded by point projection radiography in the radiation from hybrid X-pinches.It is found that the application of an artificial periodic structure to the foil leads to a much more uniform and well-defined periodic structure of the exploded foil.Images recorded in the UV range using a microchannel-plate-intensified detector show that the radiation from a surface-modified foil is more uniform along the entire length and width of the foil than that from a foil without modification. | T.A.Shelkovenko I.N.Tilikin A.V.Oginov A.R.Mingaleev V.M.Romanova S.A.Pikuz | 2023 | Matter and Radiation at Extremes2023，8，5： | 0 |
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