A5062901980- Laser-Plasma Interactions and Diagnostics
- Laser-induced spectroscopy and plasma
- Magnetic confinement fusion research
- Solar and Space Plasma Dynamics
- Nuclear Physics and Applications
- High-pressure geophysics and materials
- Ionosphere and magnetosphere dynamics
- Laser-Matter Interactions and Applications
- Plasma Diagnostics and Applications
- Particle accelerators and beam dynamics
- Astro and Planetary Science
- Astrophysics and Star Formation Studies
- Optical Polarization and Ellipsometry
- Pulsed Power Technology Applications
- Electromagnetic Launch and Propulsion Technology
- Gamma-ray bursts and supernovae
- Dust and Plasma Wave Phenomena
- Advanced X-ray Imaging Techniques
- Cold Fusion and Nuclear Reactions
- Atomic and Molecular Physics
- Laser Design and Applications
- Planetary Science and Exploration
- Gyrotron and Vacuum Electronics Research
- High voltage insulation and dielectric phenomena
- Radiation Therapy and Dosimetry
Imperial College London
2018-2024
Lawrence Livermore National Laboratory
2020-2024
University of York
2014-2021
Université de Bordeaux
2020
Commissariat à l'Énergie Atomique et aux Énergies Alternatives
2020
Centre Lasers Intenses et Applications
2020
Centre National de la Recherche Scientifique
2020
Rutherford Appleton Laboratory
2017-2019
Optical Sciences (United States)
2019
University of Michigan
2019
An inertial fusion implosion on the National Ignition Facility, conducted August 8, 2021 (N210808), recently produced more than a megajoule of yield and passed Lawson's criterion for ignition [Phys. Rev. Lett. 129, 075001 (2022)]. We describe experimental improvements that enabled N210808 present first measurements from an igniting plasma in laboratory. metrics like product hot-spot energy pressure squared, absence self-heating, increased by ∼35%, leading to record values enhancement...
We present the design of first igniting fusion plasma in laboratory by Lawson's criterion that produced 1.37 MJ energy, Hybrid-E experiment N210808 (August 8, 2021) [Phys. Rev. Lett. 129, 075001 (2022)10.1103/PhysRevLett.129.075001]. This uses indirect drive inertial confinement approach to heat and compress a central "hot spot" deuterium-tritium (DT) fuel using surrounding dense DT piston. Ignition occurs when heating from absorption α particles created process overcomes loss mechanisms...
We report the first experimental demonstration of a plasma wave plate based on laser-induced birefringence. An elliptically polarized input was converted into nearly ideal circularly beam using an optical system composed second laser and plasma. The results are in excellent agreement with linear theory three-dimensional simulations up to phase delays exceeding π/4, thus establishing feasibility laser-plasma photonic devices that ultrafast, damage-resistant, easily tunable.
This study investigated discrepancies between measured and simulated x-ray drive in Inertial Confinement Fusion (ICF) hohlraums at the National Ignition Facility (NIF). Despite advances radiation-hydrodynamic simulations, a consistent "drive deficit" remains. Experimentally ICF capsule bang-times are systematically 400-700 ps later than simulations predict. The Build-A-Hohlraum (BAH) campaign explored potential causes for this discrepancy by varying hohlraum features, including laser...
The ability to control laser pre-heat is an integral part of the inertial confinement fusion concept known as Magnetized Liner Inertial Fusion. This process studied at National Ignition Facility (NIF) where 4 192 beams are propagated through a 1-cm long gas cell they deposit >20 kJ energy into gaseous fuel via inverse bremsstrahlung absorption. ionizes gas, producing plasma that follows behind front and expands over radius cell. Emission from this plasma, viewed by gated x-ray...
This study investigated discrepancies between measured and simulated x-ray drive in Indirect-Drive Inertial Confinement Fusion (ID-ICF) hohlraums at the National Ignition Facility. Despite advances radiation-hydrodynamic simulations, a consistent “drive deficit” remains. Experimentally ID-ICF capsule bang-times are systematically 400–700 ps later than simulations predict. The Build-A-Hohlraum (BAH) campaign explored potential causes for this discrepancy by varying hohlraum features,...
Magnetic reconnection is a process that contributes significantly to plasma dynamics and energy transfer in wide range of magnetic field regimes, including inertial confinement fusion experiments, stellar coronae, compact, highly magnetized objects like neutron stars. Laboratory experiments different regimes can help refine, expand, test the applicability theoretical models describe reconnection. Laser-plasma exploring at moderate intensity (IL ∼ 1014 W cm−2) have been performed previously,...
Abstract Magnetized plasma interactions are ubiquitous in astrophysical and laboratory plasmas. Various physical effects have been shown to be important within colliding flows influenced by opposing magnetic fields, however, experimental verification of the mechanisms interaction region has remained elusive. Here we discuss a laser-plasma experiment whereby results verify that Biermann battery generated fields advected Nernst anisotropic pressure dominate these reconnection region. These...
Optical collective Thomson scattering (TS) is used to diagnose magnetized high energy density physics experiments at the Magpie pulsed-power generator Imperial College London. The system uses an amplified pulse from second harmonic of a Nd:YAG laser (3 J, 8 ns, 532 nm) probe wide diversity high-temperature plasma objects, with densities in range 1017–1019 cm−3 and temperatures between 10 eV few keV. scattered light collected 100 μm-scale volumes within plasmas, which are imaged onto optical...
We present experimental measurements of a pulsed plasma gun, using two-colour imaging laser interferometry and spatially resolved Thomson scattering. Interferometry give an electron density cm−3 at the centre plume, 5 mm from gun nozzle. The scattered light is collected two probing angles allowed us to simultaneously measure collective non-collective spectrum feature same spatial locations. inferred densities location waves in agreement with interferometry. temperatures spectra are not...
By analyzing profiles of experimental x-ray spectral lines Si XIV and Al XIII, we found that both Langmuir ion acoustic waves developed in plasmas produced via irradiation thin foils by relativistic laser pulses (intensities ~10 21 W/cm 2 ).We prove these are due to the parametric decay instability (PDI).This is first time PDI-induced turbulence was discovered spectroscopy laserproduced plasmas.These conclusions also supported PIC simulations.Our results can be used for laboratory modeling...
Abstract A supersonic flow of magnetized plasma is produced by the application a 1 MA-peak, 500 ns current pulse to cylindrical arrangement parallel wires, known as an inverse wire array. The J × B acceleration ablated material, and magnetic field several Tesla embedded at source driving current. This setup has been used for variety experiments investigating interactions flows. In designed investigate reconnection, collision counter-streaming flows, carrying oppositely directed fields, leads...
Astrophysical flows exhibit rich behaviour resulting from the interplay of different forms energy-gravitational, thermal, magnetic and radiative. For cataclysmic variable stars, material a late, main sequence star is pulled onto highly magnetized (B>10 MG) white dwarf. The field sufficiently large to direct flow as an accretion column poles dwarf, subclass known AM Herculis. A stationary radiative shock expected form 100-1,000 km above surface far too small be resolved with current...
Hot electron preheat has been quantified in warm, directly driven inertial confinement fusion implosions on OMEGA and the National Ignition Facility (NIF), to support hydrodynamic scaling studies. These CH-shell experiments were designed be hydrodynamically equivalent, spanning a factor of 40 laser energy 3.4 spatial temporal scales, while preserving incident intensity 1015 W/cm2. Experiments with similarly low levels beam smoothing NIF show similar fraction (∼0.2%) deposited as hot...
Recent results on crossed-beam energy transfer are presented. Wavelength tuning was used to vary the amount of between two beams in a quasi-stationary plasma with carefully controlled conditions. The agreed well calculations assuming linear ion acoustic waves (IAWs) amplitudes up . Increasing initial probe intensity access larger IAW for otherwise fixed conditions yields evidence saturation. ability manipulate beam's polarization, which from anisotropic nature interaction, is revisited; an...
We report on the first observation of high-n hollow ions (ions having no electrons in K or L shells) produced Si targets via pumping by ultra-intense x-ray radiation intense laser-plasma interactions reaching dominant kinetics regime.The existence these new types high energy density plasma has been found highly-resolved emission spectra silicon plasma, and confirmed calculations, underscoring ability powerful sources to fully strip from inner-most shells light atoms.Hollow spectral...
Laser propagation experiments using four beams of the National Ignition Facility to deliver up 35 kJ laser energy at 351 nm wavelength heat magnetized liner inertial fusion-scale (1 cm-long), hydrocarbon-filled gas pipe targets ∼keV electron temperatures have demonstrated coupling >20 with essentially no backscatter in 15% critical density fills 0–19 T applied axial magnetic fields. The is also investigated for an 11.5% and field strengths 24 both densities. This spans a range Hall...
This work presents a magnetic reconnection experiment in which the kinetic, magnetic, and thermal properties of plasma each play an important role overall energy balance structure generated layer. Magnetic occurs during interaction continuous steady flows super-Alfvénic, magnetized, aluminum plasma, collide geometry with two-dimensional symmetry, producing stable long-lasting Optical Thomson scattering measurements show that when layer forms, ions inside are more strongly heated than...
We report on the first direct voltage and current measurements from a laser-generated magnetic field coil target. The was observed to scale with laser intensity as B∝Ilaser0.66±0.13. This scaling relation can be derived measured approximated by laser-heated plasma electron temperature Te. experiments used 1053 nm pulse lengths ranging 0.5 20 ns intensities 109 1014W/cm2 generate an electric potential that drives through coil. show behavior of described lumped-element circuit model.
Laser-driven Hohlraums filled with gas at lower densities (<0.6 mg/cc) have higher efficiency compared to original ≥ 0.96 mg/cc fill because of reduced backscatter losses [Hall et al., Phys. Plasmas 24, 052706 (2017)]. However, using low-density longer drive required for adiabat implosions, and hence potentially inertial confinement fusion gain designs, has been challenging since the Hohlraum wall blow-off is less tamped, thus altering laser beam absorption regions symmetry. A series...
Recent pulsed-power experiments have demonstrated the formation of astrophysically relevant, differentially rotating plasmas. Key features plasma flows are discovery a quasi-Keplerian rotation curve, launching highly collimated angular-momentum-transporting axial jets, and hollow density structure sustained by centrifugal barrier effect. In this communication, we discuss several in these through order-of-magnitude models. First, show that observed velocity would produce force strong enough...
Fast analysis of collective Thomson scattering ion acoustic wave features using a deep convolutional neural network model is presented. The was trained from spectra to predict the plasma parameters, including velocities, population fractions, and electron temperatures. A fully kinetic particle-in-cell simulation used laboratory astrophysics experiment simulate diagnostic image feature. Network predictions were compared with Bayesian inference parameters for both simulated experimentally...
We describe a versatile pulsed-power driven platform for magnetic reconnection experiments, based on the exploding wire arrays in parallel [Suttle et al., Phys. Rev. Lett. 116, 225001 (2016)]. This produces inherently magnetised plasma flows duration of generator current pulse (250 ns), resulting long-lasting layer. The layer exists long enough to allow evolution complex processes such as plasmoid formation and movement be diagnosed by suite high spatial temporal resolution laser-based...
We present X-ray spectroscopic diagnostics in femto-second laser-driven experiments revealing nonlinear phenomena caused by the strong coupling of laser radiation with created plasma. Among those phenomena, we found signatures Two Plasmon Decay (TPD) instability a CO2 cluster-based plasma analyzing Langmuir dips profile O VIII Lyε line, waves at high intensity 3 1018Wcm-2. With similar intensities, reveal also phenomenon Second Harmonic Generation (SHG) frequency satellites Lyman δ and ε...
We present a new experimental platform for studying radiative shocks using an “inverse liner z-pinch” configuration. This was tested on the MAGPIE pulsed power facility (~1 MA with rise time of ~240 ns) at Imperial College London, U.K. Current is discharged through thin-walled metal tube (a liner) embedded in low-density gas-fill and returned central post. The resulting magnetic pressure inside launched cylindrically symmetric, expanding shock into ~10 km/s. provides good diagnostic access,...