A5018979664- Laser-Plasma Interactions and Diagnostics
- Laser-induced spectroscopy and plasma
- Laser-Matter Interactions and Applications
- Advanced X-ray Imaging Techniques
- High-pressure geophysics and materials
- Laser Design and Applications
- Atomic and Molecular Physics
- Nuclear Physics and Applications
- Particle Accelerators and Free-Electron Lasers
- Diamond and Carbon-based Materials Research
- Laser Material Processing Techniques
- Pulsed Power Technology Applications
- Advanced X-ray and CT Imaging
- X-ray Spectroscopy and Fluorescence Analysis
- Advanced Fiber Laser Technologies
- Magnetic confinement fusion research
- Radiation Therapy and Dosimetry
- Planetary Science and Exploration
- Particle accelerators and beam dynamics
- Advanced Surface Polishing Techniques
- Ocular and Laser Science Research
- Plasma Diagnostics and Applications
- Crystallography and Radiation Phenomena
- Space Satellite Systems and Control
- Atomic and Subatomic Physics Research
Imperial College London
2016-2025
John Adams Institute for Accelerator Science
2014-2024
University of Michigan
2010-2023
Isaac Newton Institute for Mathematical Sciences
2014-2023
Plasma Technology (United States)
2021
Optical Sciences (United States)
2011-2018
University of York
2018
Rutherford Appleton Laboratory
2003-2018
TIFR Centre for Interdisciplinary Sciences
2018
Tata Institute of Fundamental Research
2018
Plasmas are an attractive medium for the next generation of particle accelerators because they can support electric fields greater than several hundred gigavolts per meter. These accelerating generated by relativistic plasma waves-space-charge oscillations-that be excited when a high-intensity laser propagates through plasma. Large currents background electrons then trapped and subsequently accelerated these waves. In forced wake field regime, where pulse length is order wavelength, we show...
The dynamics of energetic particles in strong electromagnetic fields can be heavily influenced by the energy loss arising from emission radiation during acceleration, known as reaction. When interacting with a high-energy electron beam, today's lasers are sufficiently intense to explore transition between classical and quantum reaction regimes. We present evidence collision an ultrarelativistic beam generated laser-wakefield acceleration (ϵ>500 MeV) laser pulse (a0>10). measure postcollision...
Abstract Electron–positron pair plasmas represent a unique state of matter, whereby there exists an intrinsic and complete symmetry between negatively charged (matter) positively (antimatter) particles. These play fundamental role in the dynamics ultra-massive astrophysical objects are believed to be associated with emission ultra-bright gamma-ray bursts. Despite extensive theoretical modelling, our knowledge this matter is still speculative, owing extreme difficulty recreating neutral...
Substantial energy loss in an electron beam passing through a high-intensity laser provides clear evidence of the radiation reaction, shedding light on how electrons interact with extreme electromagnetic fields.
We report on the generation of a narrow divergence (${\ensuremath{\theta}}_{\ensuremath{\gamma}}<2.5\text{ }\text{ }\mathrm{mrad}$), multi-MeV (${E}_{\mathrm{max}}\ensuremath{\approx}18\text{ }\mathrm{MeV}$) and ultrahigh peak brilliance ($>1.8\ifmmode\times\else\texttimes\fi{}{10}^{20}\text{ }\mathrm{photons}\text{ }{\mathrm{s}}^{\ensuremath{-}1}\text{ }{\mathrm{mm}}^{\ensuremath{-}2}\text{ }{\mathrm{mrad}}^{\ensuremath{-}2}$ 0.1% BW) $\ensuremath{\gamma}$-ray beam from scattering an...
Abstract Plasma-based accelerators use the strong electromagnetic fields that can be supported by plasmas to accelerate charged particles high energies. Accelerating field structures in plasma generated powerful laser pulses or particle beams. This research has recently transitioned from involving a few small-scale efforts development of national and international networks scientists substantial investment large-scale infrastructure. In this New Journal Physics 2020 Plasma Accelerator...
The acceleration of electrons to approximately 0.8 GeV has been observed in a self-injecting laser wakefield accelerator driven at plasma density 5.5x10(18) cm(-3) by 10 J, 55 fs, 800 nm pulse the blowout regime. is found be self-guided for 1 cm (>10zR), measurement single filament containing >30% initial energy this distance. Three-dimensional particle cell simulations show that intensity within guided amplified beyond its focused value normalized vector potential a0>6, thus driving highly...
The dynamics of plasma electrons in the focus a petawatt laser beam are studied via measurements their x-ray synchrotron radiation. With increasing intensity, forward directed x rays extending to 50 keV is observed. measured well described asymptotic limit oscillating channel. critical energy spectrum found scale as Maxwellian temperature simultaneously electron spectra. At low intensity transverse oscillations negligible predominantly accelerated axially by generated wakefield. high...
We report measurements of ultrahigh magnetic fields produced during intense ( approximately 10(20) Wcm(-2) micro m(2) ) laser interaction experiments with solids. show that polarization high-order vuv harmonics generated the (up to 15th order) suggest existence field strengths 0.7+/-0.1 GG in overdense plasma. Measurements using higher order indicate denser regions plasma can be probed. This technique may useful for multi- level which are predicted occur at even intensities.
A beam of multi-MeV helium ions has been observed from the interaction a short-pulse high-intensity laser pulse with underdense plasma. The ion was found to have maximum energy for He2+ (40(+3)(-8)) MeV and directional along propagation path, highest being collimated cone less than 10 degrees. 2D particle-in-cell simulations show that are accelerated by sheath electric field is produced at back gas target. This generated transfer hot electron beam, which exits target generating large...
We report experimental evidence for a Rayleigh-Taylor-like instability driven by radiation pressure of an ultraintense (${10}^{21}\text{ }\text{ }\mathrm{W}/{\mathrm{cm}}^{2}$) laser pulse. The is witnessed the highly modulated profile accelerated proton beam produced when irradiates 5 nm diamondlike carbon (90% C, 10% H) target. Clear anticorrelation between bubblelike modulations and transmitted further demonstrate role in modulating foil. Measurements modulation wavelength, acceleration...
We show that x-rays from a recently demonstrated table top source of bright, ultrafast, coherent synchrotron radiation [Kneip et al., Nat. Phys. 6, 980 (2010)] can be applied to phase contrast imaging biological specimens. Our scheme is based on focusing high power short pulse laser in tenuous gas jet, setting up plasma wakefield accelerator accelerates and wiggles electrons analogously conventional synchrotron, but the centimeter rather than tens meter scale. use record absorption images...
Experiments exploring the collision of a high-intensity laser beam with an electron are within reach modern technology. New fundamental insights into quantum electrodynamic process photon emission from accelerating electrons and new type gamma-ray sources may emerge these soon-to-be-realized experiments.
Abstract Laser wakefield accelerators promise to revolutionize many areas of accelerator science. However, one the greatest challenges their widespread adoption is difficulty in control and optimization outputs due coupling between input parameters dynamic evolution accelerating structure. Here, we use machine learning techniques automate a 100 MeV-scale accelerator, which optimized its by simultaneously varying up six including spectral spatial phase laser plasma density length. Most...
Abstract A bright μm-sized source of hard synchrotron x-rays (critical energy E crit > 30 keV) based on the betatron oscillations laser wakefield accelerated electrons has been developed. The potential this for medical imaging was demonstrated by performing micro-computed tomography a human femoral trabecular bone sample, allowing full 3D reconstruction to resolution below 50 μm. use 1 cm long accelerator means that length beamline (excluding laser) is dominated x-ray distances rather...
The spectra of energetic electrons produced by a laser interaction with underdense plasma have been measured at intensities $>3\ifmmode\times\else\texttimes\fi{}{10}^{20}\text{ }\text{ }\mathrm{W}\text{ }{\mathrm{cm}}^{\ensuremath{-}2}$. Electron energies in excess 300 MeV observed. Measurements the transmitted spectrum indicate that there is no correlation between acceleration and wave production. Particle-in-cell simulations show ponderomotive force produces an ion channel. field nonlinear...
Beam profile measurements of laser-wakefield accelerated electron bunches reveal that in the monoenergetic regime electrons are injected and at back first period plasma wave. With pulse durations ctau >or= lambda(p), we observe an elliptical beam with axis ellipse parallel to laser polarization. This increase divergence polarization direction indicates within pulse. Reducing density (decreasing ctau/lambda(p)) leads a less ellipticity, implying self-injection occurs rear also demonstrates...
Ion acceleration by the interaction of an ultraintense short-pulse laser with underdense-plasma has been studied at intensities up to $3\ifmmode\times\else\texttimes\fi{}{10}^{20}\text{ }\text{ }\mathrm{W}/\mathrm{c}{\mathrm{m}}^{2}$. Helium ions having a maximum energy $13.2\ifmmode\pm\else\textpm\fi{}1.0\text{ }\mathrm{M}\mathrm{e}\mathrm{V}$ were measured angle 100\ifmmode^\circ\else\textdegree\fi{} from propagation direction. The ion scaled plasma density as...
Positron emission tomography (PET) is a powerful diagnostic/imaging technique requiring the production of short-lived positron emitting isotopes 11C, 13N, 15O and 18F by proton irradiation natural/enriched targets using cyclotrons. The development PET has been hampered due to size shielding requirements nuclear installations. Recent results show that when an intense laser beam interacts with solid targets, megaelectronvolt (MeV) protons capable producing are generated. This report describes...
Experiments were performed to investigate the propagation of a high intensity (I approximately 10(21) W cm(-2)) laser in foam targets with densities ranging from 0.9n(c) 30n(c). Proton acceleration was used diagnose interaction. An improvement proton beam energy and efficiency is observed for lowest density (n(e)=0.9n(c)), compared higher foams. Simulations show that penetrates deeper into target due its relativistic results greater collimation ensuing hot electrons. This rear surface...
The generation of quasimonoenergetic electron beams, with energies up to 200 MeV, by a laser-plasma accelerator driven in hydrogen-filled capillary discharge waveguide is investigated. Injection and acceleration electrons found depend sensitively on the delay between onset current arrival laser pulse. A comparison spectroscopic interferometric measurements suggests that injection assisted ionization atoms or ions within channel.
In this article we review the prospects of laser wakefield accelerators as next generation light sources for applications. This work arose a result discussions held at 2013 Laser Plasma Accelerators Workshop. X-ray phase contrast imaging, x-ray absorption spectroscopy, and nuclear resonance fluorescence are highlighted potential applications laser–plasma based sources. We discuss ongoing future efforts to improve properties radiation from plasma betatron emission Compton scattering using...