We present measurements of magnetic fields generated in laser-driven coil targets irradiated by laser pulses of nanosecond duration, 1.053 μm wavelength, 500 J energy, and ∼1015 W/cm2 intensity, at the LULI2000 facility. Using two perpendicular probing axes, proton deflectometry is used to characterize the coil current and static charge at different times. Results reveal various deflection features that can be unambiguously linked to a looping quasi-steady current of well-understood polarity or to a static charging of the coil surface. Measured currents are broadly consistent with predictions from a laser-driven diode-current source and lumped circuit model, supporting the quasi-steady assessment of the discharges. Peak magnetic fields of ∼50 T at the center of 500-μm-diameter coils, obtained at the moderate laser intensity, open up the use of such laser-driven coil targets at facilities worldwide to study numerous phenomena in magnetized high-energy-density plasmas, and its potential applications.

We report new experimental results on radiative shocks obtained in Xenon and Argon in gas cells at two different pressures below 1 bar. These shock waves are generated by the interaction of the PALS iodine laser on a CH–Au foil with a typical velocity in the range of 50–100 km/s depending on the variable laser intensity, pressure, and gas. Attention is paid to the morphology and the dynamics of the radiative precursor over large time scales up to 30 ns, using 2D sub-picosecond visible interferometry, illustrating the complex interplay of hydrodynamic and radiation absorption for different initial conditions. The comparison between 1D and 2D simulations confirms the role played by lateral radiative losses in the ionization wave and the necessity of state-of-the-art integrated opacities. This study is complemented by the first XUV analysis of the shock emission between 5 and 20 nm obtained with a grating spectrometer, with line identification, which is compatible with the ionization stages deduced from interferometry and simulations.

Magnetization is a key strategy for enhancing inertial fusion performance, though accurate characterization of magnetized dense plasmas is needed for a better comprehension of the underlying physics. Measured spectra from imploding Ar-doped D2-filled cylinders at the OMEGA laser show distinctive features with and without an imposed magnetic field. A multizone spectroscopic diagnosis leads to quantitative estimates of the plasma conditions, namely revealing a 50% core temperature rise at half mass density when a 30-T seed field is applied. Concurrently, experimental spectra align well with predictions from extended-magnetohydrodynamics simulations, providing strong evidence that the attained core conditions at peak compression are consistent with the impact of a 10-kT compressed field. These results pave the way for the validation of magnetized transport models in dense plasmas and for future magnetized laser implosion experiments at a larger scale.

We present a detailed characterization of the structure and evolution of differentially rotating plasmas driven on the MAGPIE pulsed-power generator (1.4 MA peak current, 240 ns rise time). The experiments were designed to simulate physics relevant to accretion discs and jets on laboratory scales. A cylindrical aluminium wire array Z pinch enclosed by return posts with an overall azimuthal off-set angle was driven to produce ablation plasma flows that propagate inwards in a slightly off-radial trajectory, injecting mass, angular momentum and confining ram pressure to a rotating plasma column on the axis. However, the plasma is free to expand axially, forming a collimated, differentially rotating axial jet that propagates at ${\approx }100\,{\rm km}\,{\rm s}<^>{-1}$. The density profile of the jet corresponds to a dense shell surrounding a low-density core, which is consistent with the centrifugal barrier effect being sustained along the jet's propagation. We show analytically that, as the rotating plasma accretes mass, conservation of mass and momentum implies plasma radial growth scaling as $r \propto t<^>{1/3}$. As the characteristic moment of inertia increases, the rotation velocity is predicted to decrease and settle on a characteristic value ${\approx }20\,{\rm km}\,{\rm s}<^>{-1}$. We find that both predictions are in agreement with Thomson scattering and optical self-emission imaging measurements.

We present results from pulsed-power driven differentially rotating plasma experiments designed to simulate physics relevant to astrophysical disks and jets. In these experiments, angular momentum is injected by the ram pressure of the ablation flows from a wire array Z pinch. In contrast to previous liquid metal and plasma experiments, rotation is not driven by boundary forces. Axial pressure gradients launch a rotating plasma jet upward, which is confined by a combination of ram, thermal, and magnetic pressure of a surrounding plasma halo. The jet has subsonic rotation, with a maximum rotation velocity 23±3  km/s. The rotational velocity profile is quasi-Keplerian with a positive Rayleigh discriminant κ^{2}∝r^{-2.8±0.8}  rad^{2}/s^{2}. The plasma completes 0.5-2 full rotations in the experimental time frame (∼150  ns).

Analysis of experimental RCF data from dual axis proton deflectometry in laser-driven coils, identifies for the first time deflection features that can be attributed to the looping current or the static charges.

First Light Fusion Ltd. (FLF) is a UK privately funded company researching energy generation using Inertial Confinement Fusion (ICF). Efforts are centered around developing both simulation and experimental capabilities. For this, FLF currently operates a pair of two-stage light gas guns with projectile velocities exceeding 7 km/s. Our electromagnetic launch capabilities include two low inductance capacitor bank pulsed power generators delivering 3.5 MA in 600 ns and 14 MA in 2 us. Experimental campaigns are focused on validation of Hytrac (multi-material hydro with front tracking and AMR) and B2 (parallel multi-material resistive MHD) codes, two simulation tools developed by FLF. This improves our understanding of target physics and electro-magnetic launch for projectile driven fusion experiments. Supporting our experimental facilities, world class diagnostic capabilities have been established at FLF. These include ultra-high-speed (~ 3 ns exposure) and streaked optical imaging, spectroscopy, VISAR and x-ray radiography. Rapid feedback between experiments and simulations enables iteration within experimental campaigns and continuous improvement of the designs.

The implosion of fast, convergent shock waves driven via the electrical explosion of cylindrical wire arrays embedded in insulator offers a highly efficient method of generating extreme pressures. At low currents (~30kA) the increased density on axis was directly observed at the ESRF synchroton; at higher currents - up to 2.5MA on the Cepage generator at First Light Fusion - the implosion dynamics imply pressures >Mbar exist in warm dense plasma on axis. How this process scales to currents >5MA is unclear - a limit could exist on the speed at which the shockwaves are initially projected from the wires, set by the rate of energy deposition into the wires.

We present the design, numerical simulations, and results of magnetized cylindrical implosions performed at the OMEGA facility. The cylindrical targets are filled with Ar-doped D 2 gas and are symmetrically imploded using a 36-beam, 15 kJ, 1.5 ns laser drive. The implosions are magnetized using the MIFEDS capability, delivering a seed B-field of 24 T along the axis of the cylindrical targets. X-ray framed imaging is used to characterize the implosions; the effect of magnetization on the compressed core conditions is obtained via Ar K-shell emission and measurements of primary neutrons.

Investigating the potential benefits of the use of magnetic fields in inertial confinement fusion experiments has given rise to experimental platforms like the Magnetized Liner Inertial Fusion approach at the Z-machine (Sandia National Laboratories) or its laser-driven equivalent at OMEGA (Laboratory for Laser Energetics). Implementing these platforms at MegaJoule-scale laser facilities, such as the Laser MegaJoule (LMJ) or the National Ignition Facility (NIF), is crucial to reaching self-sustained nuclear fusion and enlarges the level of magnetization that can be achieved through a higher compression. In this paper, we present a complete design of an experimental platform for magnetized implosions using cylindrical targets at LMJ. A seed magnetic field is generated along the axis of the cylinder using laser-driven coil targets, minimizing debris and increasing diagnostic access compared with pulsed power field generators. We present a comprehensive simulation study of the initial B field generated with these coil targets, as well as two-dimensional extended magnetohydrodynamics simulations showing that a 5 T initial B field is compressed up to 25 kT during the implosion. Under these circumstances, the electrons become magnetized, which severely modifies the plasma conditions at stagnation. In particular, in the hot spot the electron temperature is increased (from 1 keV to 5 keV) while the density is reduced (from 40g/cm^{3} to 7g/cm^{3}). We discuss how these changes can be diagnosed using x-ray imaging and spectroscopy, and particle diagnostics. We propose the simultaneous use of two dopants in the fuel (Ar and Kr) to act as spectroscopic tracers. We show that this introduces an effective spatial resolution in the plasma which permits an unambiguous observation of the B-field effects. Additionally, we present a plan for future experiments of this kind at LMJ.

Magnetization of inertial confinement implosions is a promising means of improving their performance, owing to the potential reduction of energy losses within the target and mitigation of hydrodynamic instabilities. In particular, cylindrical implosions are useful for studying the influence of a magnetic field due to their axial symmetry. Here we present results from magnetized cylindrical implosion experiments on the OMEGA-60 laser using a 40-beam, 14.5 kJ, 1.5 ns drive and an initial seed magnetic field of B0 = 24T along the axis of the targets. Implosions were characterized using time-resolved X-ray imaging from two orthogonal lines of sight. Measurements of shell implosion dynamics suggest there is no significant difference between the magnetized and non-magnetized cases, in line with Gorgon extended magnetohydrodynamic simulations. However, the location of the imploding shell - inferred from a peak in the bremsstrahlung X-ray emission profile - was systematically offset from the simulations. The experimental setup allowed us to follow the full implosion of the targets until stagnation, resulting in a convergence ratio of ~20 compared to the expected value of ~50-60 predicted by the simulations.

This paper uses extended-magnetohydrodynamics (MHD) simulations to explore an extreme magnetized plasma regime realizable by cylindrical implosions on the OMEGA laser facility. This regime is characterized by highly compressed magnetic fields (greater than 10 kT across the fuel), which contain a significant proportion of the implosion energy and induce large electrical currents in the plasma. Parameters governing the different magnetization processes such as Ohmic dissipation and suppression of instabilities by magnetic tension are presented, allowing for optimization of experiments to study specific phenomena. For instance, a dopant added to the target gas-fill can enhance magnetic flux compression while enabling spectroscopic diagnosis of the imploding core. In particular, the use of Ar K-shell spectroscopy is investigated by performing detailed non-LTE atomic kinetics and radiative transfer calculations on the MHD data. Direct measurement of the core electron density and temperature would be possible, allowing for both the impact of magnetization on the final temperature and thermal pressure to be obtained. By assuming the magnetic field is frozen into the plasma motion, which is shown to be a good approximation for highly magnetized implosions, spectroscopic diagnosis could be used to estimate which magnetization processes are ruling the implosion dynamics; for example, a relation is given for inferring whether thermally driven or current-driven transport is dominating.

Magnetization of inertial confinement implosions is a promising means of improving their performance, owing to the potential reduction of energy losses within the target and mitigation of hydrodynamic instabilities. In particular, cylindrical implosions are useful for studying the influence of a magnetic field, thanks to their axial symmetry. Here, we present experimental results from cylindrical implosions on the OMEGA-60 laser using a 40-beam, 14.5 kJ, 1.5 ns drive and an initial seed magnetic field of B0 = 30 T along the axes of the targets, compared with reference results without an imposed B-field. Implosions were characterized using time-resolved x-ray imaging from two orthogonal lines of sight. We found that the data agree well with magnetohydrodynamic simulations, once radiation transport within the imploding plasma is considered. We show that for a correct interpretation of the data in these types of experiments, explicit radiation transport must be taken into account.

The termination regions of non-relativistic jets in protostars and supersonic outflows in classical novae are nonthermal emitters. Given the high densities in these systems, radiative shocks are expected to form. However, in the presence of high velocities, the formation of adiabatic shocks is also possible. A case of interest is when the two types of shocks occur simultaneously. These dense jets/outflows are excellent candidates for laboratory experiments as demonstrated by MHD scaling. We aim at studying the combination of adiabatic and radiative shocks in these systems. We focus on determining the conditions under which this combination is feasible together with its physical implications. We perform an analytical study of the shocks in both types of sources for a set of parameters. The hydrodynamical evolution of a jet colliding with an ambient medium is studied with 2D numerical simulations confirming our initial theoretical estimates. We show that for a wide set of parameters the combination of an adiabatic and a radiative shock is possible at the working surface of the termination region in jets from young stars and novae outflows. We find that instabilities are developed at the contact discontinuity, mixing the shocked materials. Also, we explore the MHD parameter scaling required for studying protostellar jets and novae outflows using laboratory experiments on laser facilities. The coexistence of an adiabatic and a radiative shock is expected at the termination region of protostellar jets and novae outflows. This scenario is very promising for particle acceleration and gamma-ray emission. The parameters for scaled laboratory experiments are very much in line with plasma conditions achievable in currently operating high-power laser facilities. This opens the door to new means for studying novae outflows never considered before.

We describe a versatile pulsed-power driven platform for magnetic reconnection experiments, based on the exploding wire arrays driven in parallel [Suttle et al., Phys. Rev. Lett. 116, 225001 (2016)]. This platform produces inherently magnetised plasma flows for the duration of the generator current pulse (250 ns), resulting in a long-lasting reconnection layer. The layer exists for long enough to allow the evolution of complex processes such as plasmoid formation and movement to be diagnosed by a suite of high spatial and temporal resolution laser-based diagnostics. We can access a wide range of magnetic reconnection regimes by changing the wire material or moving the electrodes inside the wire arrays. We present results with aluminium and carbon wires, in which the parameters of the inflows and the layer that forms are significantly different. By moving the electrodes inside the wire arrays, we change how strongly the inflows are driven. This enables us to study both symmetric reconnection in a range of different regimes and asymmetric reconnection.