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We present a study on the impact of a gas atmosphere on the collision of two counterpropagating plasmas (gold and carbon). Imaging optical Thomson scattering data of the plasma collision with and without helium in between have been obtained at the Omega laser facility. Without gas, we observed large scale mixing of colliding gold and carbon ions. Once ambient helium is added, the two plasmas remain separated. The difference in ionic temperature is consistent with a reduction of the maximum Mach number of the flow from $M=7$ to $M=4$. It results in a reduction of a factor $\ensuremath{\sim}10$ of the counterstreaming ion-ion mean free path. By adding a low-density ambient gas, it is possible to control the collision of two high-velocity counterstreaming plasma, transitioning from an interpenetrating regime to a regime in agreement with a hydrodynamic description.

The equations of state tables used in Inertial Confinement Fusion Capsule design tools are highly dependent on the cold curve in the multimegabar pressure range. Original ab initio molecular dynamic simulations were performed to get accurate cold curves of glow-discharge polymer (GDP) plastics. Furthermore the effect of oxygen absorption by GDP structure is studied on the cold curve, as well as its impact on the Hugoniot curves. Results are compared with the Hugoniot experimental data obtained in a recent experiment at the LULI2000 laser facility in France. This study leads to improve the equation of states knowledge of ablator materials, which is of primary importance for NIF and LMJ experiments.

In this article, we investigate the kinetics of the iron $\ensuremath{\alpha}\ensuremath{-}\ensuremath{\varepsilon}$ transition under laser-driven ramp compression for deformation rates ranging from 3 to $9\ifmmode\times\else\texttimes\fi{}{10}^{7}\phantom{\rule{0.28em}{0ex}}{\mathrm{s}}^{\ensuremath{-}1}$. As in previous work, we observe a plateau in the rear surface velocity profile at the transition. With increasing deformation rate the transition onset pressure raises from 11 to 25 GPa, while the plateau duration decreases. These kinetic effects are well reproduced by an Avrami-type kinetics model of nucleation and growth with a constant, nanosecond scale completion time, which suggests an isokinetic regime over the explored range of strain rates.

The Near Vacuum Campaign on the National Ignition Facility has sparked an interest on the nature of the gold/carbon interface at high velocity (400 km/s), high electron temperature (2 keV), low-electron density (1e21). Indeed radiation-hydrodynamic simulations using the code HYDRA have been unable to accurately reproduce the experimental shape of the hot spot resulting from implosion driven in Near Vacuum Holhraum. The experimental data are suggesting that the NIF inner beams are freely propagating to the waist of the hohlraum when the simulations predict that a density ridge at the gold/carbon interface blocks the inner beams. The discrepancy between experimental data and simulation might be explained by the fluid description of the plasma interface in a rad-hydro code which is probably not valid in when two plasma at high velocity, high temperature are meeting in a Near Vacuum Hohlraum. To test our assumption that a kinetic description is more appropriate in this regime, we went to the Omega laser facility to study gold/carbon interface in the relevant regime. We will present results comparing the plasma interface of a C/C, Al/C and Au/C under the same laser drive. Time resolved images of the self-emission of the interface as well as Thomson scattering data will be presented.

Glow discharge polymer hydrocarbon (GDP-CH) is used as the ablator material in inertial confinement fusion (ICF) capsules for the Laser Megajoule and National Ignition Facility. Due to its fabrication process, GDP-CH chemical composition and structure differ from commercially available plastics and detailed knowledge of its properties in the warm dense matter regime is needed to achieve accurate design of ICF capsules. First-principles ab initio simulations of the GDP-CH principal Hugoniot up to 8 Mbar were performed using the quantum molecular dynamics (QMD) code abinit and showed that atomic bond dissociation has an effect on the compressibility. Results from these simulations are used to parametrize a quantum semiempirical model in order to generate a tabulated equation of state that includes dissociation. Hugoniot measurements obtained from an experiment conducted at the LULI2000 laser facility confirm QMD simulations as well as EOS modeling. We conclude by showing the EOS model influence on shock timing in a hydrodynamic simulation.

Pressure, density, and temperature were measured along the principal Hugoniot of the Si-doped Glow Discharge Polymer used in Inertial Confinement Fusion (ICF) capsules up to 5 Mbar, covering conditions beyond the first shock in a full-scale Inertial Confinement Fusion (ICF) capsule. The experiments were performed using the GEKKOXII laser at the Institute of Laser Engineering at Osaka University in Japan. Results are in good agreement with predictions obtained from ab initio Hugoniot calculations, but softer than the quotidian equation of state average atom model. Ab initio calculations show that dissociation of carbon bonds need to be taken into account in order to explain Hugoniot compressibility.

Plastic materials (CH) doped with mid-Z elements are used as ablators in inertial confinement fusion (ICF) capsules and in their surrogates. Hugoniot equation of state (EOS) and electronic properties of CH doped with germanium (at 2.5% and 13% dopant fractions) are investigated experimentally up to 7 Mbar using velocity and reflectivity measurements of shock fronts on the GEKKO laser at Osaka University. Reflectivity and temperature measurements were updated using a quartz standard. Shocked quartz reflectivity was measured at 532 and 1064 nm. Theoretical investigation of shock pressure and reflectivity was then carried out by ab initio simulations using the quantum molecular dynamics (QMD) code abinit and compared with tabulated average atom EOS models. We find that shock states calculated by QMD are in better agreement with experimental data than EOS models because of a more accurate description of ionic structure. We finally discuss electronic properties by comparing reflectivity data to a semiconductor gap closure model and to QMD simulations.

The ablator material for inertial confinement fusion (ICF) capsules on the Laser Megajoule is a glow-discharge polymer (GDP) plastic. Its equation of state (EOS) is of primary importance for the design of such capsules, since it has direct consequences on shock timing and is essential to mitigate hydrodynamic instabilities. Using ab initio molecular dynamics (AIMD), we have investigated the 300-K isotherm of amorphous CH(1.37)O(0.08) plastic, whose structure is close to GDP plastic. The 300-K isotherm, which is often used as a cold curve within tabular EOS, is an important contribution of the EOS in the multimegabar pressure range. AIMD results are compared to analytic models within tabular EOS, pointing out large discrepancies. In addition, we show that the effect of oxygen decreases 300-K isotherm pressure by 10%-15%. The implication of these observations is the ability to improve ICF target performance, which is essential to achieve fusion ignition.

In this paper, we report on the quasi-isentropic compression of an iron sample using ramp shaped laser irradiation. This technique allows us to quasi-isentropically compress iron up to 700 GPa and 8500 K. To our knowledge, these data are the highest pressures reached on iron in off-Hugoniot conditions and the closest to the thermodynamic states thought to exist in Earth-like planetary cores. The experiment was performed on the Ligne d'Integration laser facility at CESTA, Bordeaux, France.

International audience; During the last ten years, the ability of high power lasers to generate high energy density shocks has made them a reliable tool to study extreme states of matter. These states of matter are relevant in many important physics areas such as astrophysics, planetology and ICF physics. Here, we present some representative studies performed by using a driven laser shock: melting of iron at pressures relevant for geophysics, developments of new techniques to measure the density of highly compressed matter and a study of a radiative shock.

New laser-driven flyer impact experiments have been performed at the LULI laboratory. In these experiments, three types of targets (single Al flyer, multi-layered, and foam-buffered high-Z metal) were used. Impacted conditions in fused quartz were measured with rear-side (two VISARs and SOP) and transverse diagnostics (shadowgraph). In the foam-buffered target, Ta foil was accelerated up to a velocity of 55 km/s. Shock wave accelerated in fused quartz by an Al flyer impact was generated, and the shock wave passing a distinct boundary to a conductive state was directly observed. This method is a way to create unique conditions within the EOS diagram of material.

Germanium-doped CH (CHGe) is one nominal ablator for LMJ target design. To investigate its properties we performed indirect drive planar Rayleigh-Taylor experiments on the OMEGA laser facility [1]. On each shot foil motion and modulations growth were simultaneously measured by side-on and face-on radiography, while drive was assessed by measuring radiation escaping through the hohlraum laser-entrance-hole (LEH). This complete set of data allows a more stringent comparison between the hydrocode simulations and the experimental results. We compare CHGe perturbations growth with those acquired on CHBr in the same experimental configuration. These preliminary results are the first step toward a test-bed validation of CH(Ge) as an ablator on OMEGA and further on LiL [2].

In the last few years, high power lasers have demonstrated the possibility to explore a new state of matter, the so-called warm dense matter. Among the possible techniques utilized to generate this state, we present the dynamic compression technique using high power lasers. Applications to planetary cores material (iron) will be discussed. Finally new diagnostics such as proton and hard-x-ray radiography of a shock propagating in a solid target will be presented.

High power lasers are a tool that can be used to determine important parameters in the context of Warm Dense Matter, i.e. at the convergence of low-temperature plasma physics and finite-temperature condensed matter physics. Recent results concerning planet inner core materials such as water and iron are presented. We determined the equation of state, temperature and index of refraction of water for pressures up to 7 Mbar. The release state of iron in a LiF window allowed us to investigate the melting temperature near the inner core boundary conditions. Finally, the first application of proton radiography to the study of shocked material is also discussed.

The interface velocity of iron partially releasing into a lithium fluoride (LiF) window has been measured using VISAR technique. Corrections to the fringe-per-velocity relationship are presented. A good agreement with hydrodynamic simulations is found at laser intensities

High power lasers are nowadays a tool that can be used to determine important parameters in the context of Warm Dense Matter. In this paper, the general issues that have been addressed in the last few years are presented. Recent results concerning water and iron experiments are exposed as a paradigm of laser driven shocks experiments.

First absolute equation of state measurements obtained for iron with laser driven shock waves are presented. The shock velocity and the free surface velocity of compressed iron have been simultaneously measured by using a VISAR diagnostic, and step targets. The pressure range 1–8 Mbar has been investigated, which is directly relevant to planetary physics. The experiments have been performed at the Laboratoire pour l’Utilisation des Lasers Intenses of the Ecole Polytechnique.

International audience; We present an overview of some recent theoretical and experimental results obtained on the properties of iron and silica at conditions encountered in planetary interiors. The first part is concerned with the development of x-ray absorption near edge spectroscopy in dynamical experiments using high-energy lasers as a tool to investigate phase transitions and structural changes at extreme pressure-temperature conditions for these two key constituents. The second part focuses on the development of a quasi-isentropic compression technique to achieve the pressure-temperature conditions anticipated in planetary interiors (3-10 Mbar, 5000-8000 K). The experiments were performed using the LULI, LLNL and LIL high-energy lasers' facilities. The experimental results are analyzed using first-principle simulations based on density functional theory.

International audience; The study of iron under quasi-isentropic compression using high energy lasers, might allow to understand its thermodynamical properties, in particular its melting line in conditions of pressure and temperature relevant to Earth-like planetary cores (330e1500 GPa, 5000e8000 K). However, the iron alphaepsilon solidesolid phase transition at 13 GPa favors shock formation during the quasi-isentropic compression process which can depart from the appropriate thermodynamical path. Understanding this shock formation mechanism is a key issue for being able to reproduce Earth-like planetary core conditions in the laboratory by ramp compression. In this article, we will present recent results of direct laser-driven quasi-isentropic compression experiments on iron samples obtained on the LULI 2000 and LIL laser facilities

We present an experimental determination of the ambient temperature equation of state, P(ρ/ρ0,293 K), up to 45 GPa, of the glow discharge polymer (GDP) used as a confining capsule for the fusible deuterium-tritium mixture in inertial confinement fusion experiments. An original method has been implemented to measure both the compression factor and the refractive index versus pressure. The data are obtained in a diamond anvil cell with two sample chambers of equal thickness containing, respectively, the GDP and a NaCl reference. This experimental equation of state is compared to numerical first principles simulations. Deviations are ascribed to the difficulty to simulate the detailed atomic structure of the polymer under moderate pressure.

Laser-plasma interaction is a major issue for achieving ignition in inertial confinement fusion schemes, and still a major concern for the upcoming french laser megajoule (LMJ) program. In order to mitigate the deleterious effects due to laser-plasma instabilities (LPI), clearly evidenced during the recent US National Ignition Campaign conducted on the National Ignition Facility, we use the LIL facility as a demonstrator for LPI studies. In this article, we focus on preliminary results regarding the propagation of a typical LMJ quadruplet through gas-filled hohlraums. Results on hohlraum energetics will then be discussed.

A laminated ablator is explored as an alternative concept for stabilizing the ablative Rayleigh-Taylor instability which develops in inertial fusion targets. Experiments measuring the growth of the Rayleigh-Taylor instability of laminated planar foils are reported. Consistent with both theory and simulations, a significant reduction of the perturbation growth is experimentally observed for laminated ablators in comparison to what is observed for classical uniform ablators. Such an enhanced hydrodynamic stability opens opportunities for the design of high-gain inertial fusion targets.

A high-resolution x-ray imager (HRXI) devoted to laser-plasma experiments combines two state-of-the-art technologies developed in France: a high-resolution x-ray microscope and a high-speed x-ray streak camera. The resulting streaked imager achieves spatial and temporal resolutions of approximately 5 microm and approximately 10 ps, respectively. The HXRI has recorded enhanced spatial and temporal resolution radiographs of indirectly driven targets on OMEGA. This paper describes the main features of the instrument and details the activation process on OMEGA (particularly the alignment). Recent results obtained on joint CEA/LLE radiographic OMEGA experiments will also be presented.

Experimental investigation of stimulated Raman (SRS) and Brillouin (SBS) scattering have been obtained at the Ligne-d'Integration-Laser facility (LIL, CEA-Cesta, France). The parametric instabilities (LPI) are driven by firing four laser beamlets (one quad) into millimeter size, gas-filled hohlraum targets. A quad delivers energy on target of 15 kJ at 3ω in a 6-ns shaped laser pulse. The quad is focused by means of 3ω gratings and is optically smoothed with a kinoform phase plate and with smoothing by spectral dispersion-like 2 GHz and/or 14 GHz laser bandwidth. Open- and closed-geometry hohlraums have been used, all being filled with 1-atm, neo-pentane (C5H12) gas. For SRS and SBS studies, the light backscattered into the focusing optics is analyzed with spectral and time resolutions. Near-backscattered light at 3ω and transmitted light at 3ω are also monitored in the open geometry case. Depending on the target geometry (plasma length and hydrodynamic evolution of the plasma), it is shown that, at maximu...

Summary form only given. Accurate phase diagrams for simple molecular fluids (H/sub 2/, H/sub 2/O, NH/sub 3/ and CH/sub 4/) and their constituent elements at temperatures of several thousand Kelvin and pressures of several Mbar are integral to planetary models of the gas giant planets ( Jupiter, Saturn, Uranus and Neptune). Experimental data at high pressure has, until recently, been limited to around I Mbar. These pressures are usually achieved dynamically with explosives and two-stage light-gas guns, or statically with diamond anvil cells. Current high intensity laser facilities can produce tens of Mbar pressures in these light fluids. This presentation will first describe recent shock compressed Hugoniot data for water at pressures up to 8 Mbar. At Hugoniot pressures near I Mbar, water becomes an electronic conductor as observed through the shock front reflectivity. Similar experimental results will be shown for carbon starting from the diamond phase. Reflectivity data reveal diamond metalizes near the Hugoniot pressure of 11 Mbar and is perhaps coincident with the melt transition. To obtain high pressure data very close to planetary isentropes, techniques are being developed to generate off Hugoniot data (lower temperature and higher density than standard Hugoniot track). Two techniques to achieve such high density states (double shock and precompressed samples) have been tested. These techniques and preliminary data from these experiments will be described.

Experiments with lasers have recently provided important improvements in our knowledge of highly compressed matter (in particular, Equation Of State). We present recent results on iron which are relevant to planetary physics. We measured the free surface velocity of the compressed iron by using a VISAR diagnostic, and the shock velocity through step targets on the same shot. An absolute EOS is then deduced for pressures 1–7 Mbar. The experiments have been performed at the LULI laboratory of the Ecole Polytechnique.

Understanding and mitigating hydrodynamic instabilities and the fuel mix are the key elements for achieving ignition in Inertial Confinement Fusion. Cryogenic indirect-drive implosions on the National Ignition Facility have evidenced that the ablative Rayleigh-Taylor Instability (RTI) is a driver of the hot spot mix. This motivates the switch to a more flexible higher adiabat implosion design [O. A. Hurricane et al., Phys. Plasmas 21, 056313 (2014)]. The shell instability is also the main candidate for performance degradation in low-adiabat direct drive cryogenic implosions [Goncharov et al., Phys. Plasmas 21, 056315 (2014)]. This paper reviews recent results acquired in planar experiments performed on the OMEGA laser facility and devoted to the modeling and mitigation of hydrodynamic instabilities at the ablation front. In application to the indirect-drive scheme, we describe results obtained with a specific ablator composition such as the laminated ablator or a graded-dopant emulator. In application to the direct drive scheme, we discuss experiments devoted to the study of laser imprinted perturbations with special phase plates. The simulations of the Richtmyer-Meshkov phase reversal during the shock transit phase are challenging, and of crucial interest because this phase sets the seed of the RTI growth. Recent works were dedicated to increasing the accuracy of measurements of the phase inversion. We conclude by presenting a novel imprint mitigation mechanism based on the use of underdense foams. The foams induce laser smoothing by parametric instabilities thus reducing the laser imprint on the CH foil.

An accurate equation of state (EOS) for planetary constituents at extreme conditions is the key to any credible model of planets or low mass stars. However, experimental validation has been carried out on at high pressure (>few Mbar), and then only on the principal Hugoniot. For planetary and stellar interiors, compression occurs from gravitational force so that material states follow a line of isentropic compression (ignoring phase separation) to ultra-high densities. An example of the predicted states for water along the isentrope for Neptune is shown in a figure. The cutaway figure on the left is from Hubbard, and the phase diagram on the right is from Cavazzoni et al. Clearly these states lie at quite a bit lower temperature and higher density than single shock Hugoniot states but they are at higher temperature than can be achieved with accurate diamond anvil experiments. At extreme densities, material states are predicted to have quite unearthly properties such as high temperature superconductivity and low temperature fusion. High density experiments on Earth are achieved with either static compression techniques (i.e.diamond anvil cells) or dynamic compression techniques using large laser facilities, gas guns, or explosives. A major thrust of this work is to develop techniques to create and characterize material states that exists primarily at the core of giant planets and brown dwarf stars. Typically, models used to construct planetary isentropes are constrained by only the planet radius, outer atmospheric spectroscopy, and space probe gravitational moment and magnetic field data. Thus any data, which provide rigid constraints for these models will have a significant impact on a broad community of planetary and condensed matter scientists. Recent laser shock wave experiments have made great strides in recreating material states that exist in the outer 25% (in radius) of the Jovian planets and at the exterior of low-mass stars. Large laser facilities have been used to compressed materials to ultra-high pressures and characterize their thermodynamic and transport properties (plastic Hugoniot to 40 Mbar, deuterium Hugoniot to 3 Mbar, metallization of ''atomic'' deuterium on the Hugoniot). To probe materials properties at these high pressures, several experimental techniques were developed high resolution radiography, optical reflectance, pyrometry, and velocity/displacement sensitive interferometry are some of the diagnostics currently used in laser-generated shock EOS experiments. During our experiments at Vulcan we developed and tested precompressed and multiple shock experimental techniques which allowed us to recreate the extreme core states of giant plants. These experiments compressed water to densities higher than accessible by single shock Hugoniot techniques and showed that the metal-insulator transition of shocked precompressed water is suppressed significantly as compared to uncompressed water. Further, as predicted the temperature of shocked precompressed water is lower than the temperature of uncompressed water enabling us to determine the metallization mechanism for water near the Hugoniot.

Indirectly driven, ablative Rayleigh–Taylor instability growth measurements in Ge-doped plastic foils were studied using face-on and side-on x-ray radiography. Laminated samples consisting of alternating layers of Ge-doped and undoped plastic and homogeneous Ge-doped foils were considered. We show for the first time that hydrodynamics do not depend upon structuration of the samples and that stabilization occurs in the case of laminated samples. All data were found to be in good agreement with bi-dimensional hydrosimulations based on theoretical and numerical predictions published earlier [L. Masse, Phys. Rev. Lett. 98, 245001 (2007)], encouraging new designs using laminated structures for ignition capsules.

We present an overview of recent experiments fielded on the LIL facility. A key issue for mega-joule class laser facilities is shrapnel fragment generation. A specific collector was therefore developed to capture debris in aerogel and dedicated shots were done to quantitatively evaluate target fragmentation phenomena. The LIL panel of transmitted and backscattered light diagnostics is well suited for laser-plasma interaction (LPI) experiments. This include gas-filled hohlraum configurations relevant to Indirect Drive ignition targets in order to test the specific LMJ longitudinal SSD technique, as well as LPI experiments with foam targets for laser beam smoothing in underdense plasma in the context of Direct Drive. After Visar commissioning a campaign was dedicated to boron Equation of State (EOS).

Results of ablative Rayleigh–Taylor instability growth experiments performed in indirect drive on the OMEGA laser facility [T. R. Boehly, D. L. Brown, S. Craxton et al., Opt. Commun. 133, 495 (1997)] are reported. These experiments aim at benchmarking hydrocodes simulations and ablator instabilities growth in conditions relevant to ignition in the framework of the Laser MegaJoule [C. Cavailler, Plasma Phys. Controlled Fusion 47, 389 (2005)]. The modulated samples under study were made of germanium-doped plastic (CHGe), which is the nominal ablator for future ignition experiments. The incident x-ray drive was provided using rugby-shaped hohlraums [M. Vandenboomgaerde, J. Bastian, A. Casner et al., Phys. Rev. Lett. 99, 065004 (2007)] and was characterized by means of absolute time-resolved soft x-ray power measurements through a dedicated diagnostic hole, shock breakout data and one-dimensional and two-dimensional (2D) side-on radiographies. All these independent x-ray drive diagnostics lead to an actual on...

The Ligne d'Integration Laser (LIL) facility has been designed as a prototype for the Laser MegaJoule (LMJ) which is a cornerstone of the French 'Simulation Program'. This laser has been intensively used to test and improve the LMJ components. In addition, a large panel of plasma diagnostics has been installed and is currently used to perform laser–plasma experiments. After a brief discussion about the LIL design, we present the last results in various plasma physics domains.

The conversion efficiency of 351nm laser light to soft x rays (0.1–5keV) was measured for Au, U, and high Z mixture “cocktails” used as hohlraum wall materials in indirect drive fusion experiments. For the spherical targets in a direct drive geometry, flattop laser pulses and laser smoothing with phase plates are employed to achieve constant and uniform laser intensities of 1014 and 1015W∕cm2 over the target surface that are relevant for the future ignition experiments at the National Ignition Facility [G. H. Miller, E. I. Moses, and C. R. Wuest, Nucl. Fusion 44, 228 (2004)]. The absolute time and spectrally resolved radiation flux is measured with a multichannel soft x-ray power diagnostic. The conversion efficiency is then calculated by dividing the measured x-ray power by the incident laser power from which the measured laser backscattering losses are subtracted. After ∼0.5ns, the time resolved x-ray conversion efficiency reaches a slowly increasing plateau of 95% at 1014W∕cm2 laser intensity and of 80...

Implosion of inertial confinement fusion (ICF) capsule is very sensitive to the growth of sphericity perturbations. The control of the feeding of such perturbations and their transport ('feedthrough') through the ablator is a key point to reach ignition. Since 2002 [1, 2], experiments have been designed and performed on the Omega laser facility in order to study these phenomena in planar geometry. A new 'rugby shaped' hohlraum was used [3, 4]. We present experimental results and comparisons with numerical simulations.

Summary form only given, as follows. Summary form only given. Accurate phase diagrams for simple molecular fluids (H/sub 2/, H/sub 2/O, NH/sub 3/ and CH/sub 4/) and their constituent elements at temperatures of several thousand Kelvin and pressures of several Mbar are integral to planetary models of the gas giant planets ( Jupiter, Saturn, Uranus and Neptune). Experimental data at high pressure has, until recently, been linuted to around 1 Mbar with both dynamic (ie. two-stage light-gas guns) and static (ie. diamond anvil cells) techniques. Current high intensity laser facilities can now produce tens of Mbar pressures in these light fluids, reaching the dense plasma states required for understanding the cores of giant planets and low mass stars. This presentation will first describe recent Hugoniot data for water at pressures up to 8 Mbar and carbon up to 30 Mbar At Hugoniot pressures near 1 Mbar, water transitions from an ionic to electronic conductor as observed from the shock front reflectivity. Pressure-densitytemperature data follow the Sesame database up to 8 Mbar where water is a dense plasma. Carbon starting from the chamond phase is shown to metallizes at Hugoniot pressures extending from 6 to 11 Mbar.

Wall and laser spot motion measurements in empty, propane-filled and plastic (CH)-lined gold coated cylindrical hohlraums were performed on the Omega laser facility [T. R. Boehly et al., Opt. Commun. 133, 495 (1997)]. Wall motion was measured using axial two-dimensional (2D) x-ray imaging and laser spot motion was perpendicularly observed through a thinned wall using streaked hard x-ray imaging. Experimental results and 2D hydrodynamic simulations show that while empty targets exhibit on-axis plasma collision, CH-lined and propane-filled targets inhibit wall expansion, corroborated with perpendicular streaked imaging showing a slower motion of laser spots.