A5020399436- Laser-Plasma Interactions and Diagnostics
- Laser-induced spectroscopy and plasma
- Laser-Matter Interactions and Applications
- High-pressure geophysics and materials
- Atomic and Molecular Physics
- Laser Design and Applications
- Advanced X-ray Imaging Techniques
- Advanced Fiber Laser Technologies
- Ion-surface interactions and analysis
- Particle Accelerators and Free-Electron Lasers
- Nuclear Physics and Applications
- Solid State Laser Technologies
- Plasma Diagnostics and Applications
- Laser Material Processing Techniques
- Astro and Planetary Science
- Radiation Therapy and Dosimetry
- Advancements in Photolithography Techniques
- Magnetic confinement fusion research
- Quantum and Classical Electrodynamics
- Particle accelerators and beam dynamics
- Laser-Ablation Synthesis of Nanoparticles
- Space Satellite Systems and Control
- Gamma-ray bursts and supernovae
- Muon and positron interactions and applications
- Radiative Heat Transfer Studies
Friedrich Schiller University Jena
2016-2024
Helmholtz Institute Jena
2012-2024
GSI Helmholtz Centre for Heavy Ion Research
2024
Schiller International University
2024
Max Planck Institute of Quantum Optics
2024
Queen's University Belfast
2008-2018
Centre of Plasma Physics - Institute for Plasma Research
2004-2007
Imperial College London
1998-2002
Protons with energies up to 18 MeV have been measured from high density laser-plasma interactions at incident laser intensities of 5x10(19) W/cm(2). Up 10(12) protons greater than 2 were observed propagate through a 125 &mgr;m thick aluminum target and measurements their angular deflection made. It is likely that the originate front surface are bent by large magnetic fields which exist in interior. To agree our these would be excess 30 MG generated beam fast electrons also observed.
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...
A stable relativistic ion acceleration regime for thin foils irradiated by circularly polarized laser pulses is suggested. In this regime, the ``light-sail'' stage of radiation pressure ions smoothly connected with initial ``hole-boring'' stage, and a defined relationship between intensity ${I}_{0}$, foil density ${n}_{0}$, thickness ${l}_{0}$ should be satisfied. For wide range required ${I}_{0}$ are theoretically estimated verified particle-in-cell code ILLUMINATION. It shown first time 2D...
The first evidence of x-ray harmonic radiation extending to 3.3 \AA{}, 3.8 keV (order $n>3200$) from petawatt class laser-solid interactions is presented, exhibiting relativistic limit efficiency scaling ($\ensuremath{\eta}\ensuremath{\sim}{n}^{\ensuremath{-}2.5}--{n}^{\ensuremath{-}3}$) at multi-keV energies. This holds up a maximum order, ${n}_{\mathrm{RO}}\ensuremath{\sim}{8}^{1/2}{\ensuremath{\gamma}}^{3}$, where $\ensuremath{\gamma}$ the Lorentz factor, above which an intensity...
The generation of ultrarelativistic positron beams with short duration (τ(e+) ≃ 30 fs), small divergence (θ(e+) 3 mrad), and high density (n(e+) 10(14)-10(15) cm(-3)) from a fully optical setup is reported. detected beam propagates high-density electron γ rays similar spectral shape peak energy, thus closely resembling the structure an astrophysical leptonic jet. It envisaged that this experimental evidence, besides intrinsic relevance to laser-driven particle acceleration, may open pathway...
Measurements of energetic proton production resulting from the interaction high-intensity laser pulses with foil targets are described. Through use layered and heating target material we able to distinguish three distinct populations protons. One high energy population is associated a source near front surface observed be emitted characteristic ring structure. A typically lower energy, divergence protons originates rear target. Finally, qualitatively separate even ions large divergence....
Selective enhancement ($>{10}^{3}$) of harmonics extending to the water window ($\ensuremath{\sim}4\text{ }\text{ }\mathrm{nm}$) generated in an argon gas filled straight bore capillary waveguide is demonstrated. This good agreement with modeling which indicates that multimode quasi-phase-matching achieved by rapid axial intensity modulations caused beating between fundamental and higher-order modes. Substantial pulse energies ($>10\text{ }\mathrm{nJ}$ per harmonic order) at wavelengths...
A new ion radiation-pressure acceleration regime, the "leaky light sail," is proposed which uses sub-skin-depth nanometer foils irradiated by circularly polarized laser pulses. In foil partially transparent, continuously leaking electrons out along with transmitted field. This feature can be exploited a multispecies nanofoil configuration to stabilize of component, supplementing latter an excess leaked from those associated heavy ions avoid Coulomb explosion. It shown 2D particle-in-cell...
Abstract The properties of beams high energy protons accelerated during ultraintense, picosecond laser-irradiation thin foil targets are investigated as a function preplasma expansion at the target front surface. Significant enhancement in maximum proton and laser-to-proton conversion efficiency is observed optimum density gradients, due to self-focusing incident laser pulse. For very long expansion, propagating pulse filament, resulting highly uniform beams, but with reduced flux energy.
Measurements of magnetic fields generated during ultrahigh intensity (>1019 W cm−2), short pulse (0.7–1 ps) laser–solid target interaction experiments are reported. An innovative method is used and the results compared with particle-in-cell simulations. It shown that polarization measurements self-generated harmonics laser can provide a convenient for diagnosing field—and experimental indicate existence peak greater than 340 MG below 460 at such high intensities. In particular,...
A scheme for enhanced quantum electrodynamics (QED) production of electron-positron-pair plasmas is proposed that uses two ultraintense lasers irradiating a thin solid foil from opposite sides. In the scheme, under proper matching condition, in addition to skin-depth emission $\ensuremath{\gamma}$-ray photons and Breit-Wheeler creation pairs on each side foil, large number high-energy electrons one can propagate through it interact with laser other side, leading much pair production. More...
Ion-acceleration processes have been studied in ultraintense laser plasma interactions for normal incidence irradiation of solid deuterated targets via neutron spectroscopy. The experimental spectra strongly suggest that the ions are preferentially accelerated radially, rather than into bulk material from three-dimensional Monte Carlo fitting spectra. Although system has a ${10}^{\ensuremath{-}7}$ contrast ratio, two-dimensional magnetic hydrodynamics simulation shows pedestal generates...
We present a design for pixelated scintillator based gamma-ray spectrometer non-linear inverse Compton scattering experiments. By colliding laser wakefield accelerated electron beam with tightly focused, intense pulse, photons up to 100 MeV energies and few femtosecond duration may be produced. To measure the energy spectrum angular distribution, 33 × 47 array of cesium-iodide crystals was oriented such that crystal length axis parallel in vertical direction. Using an iterative deconvolution...
Basic and integrated studies are conducted on fast ignition (FI) using various large laser systems. A Peta watt (PW) system is used to study the basic elements relevant FI can also be injected a compressed core test experiment when coupled with GEKKO twelve beam system. Using spherical target inserted Au cone guide for PW pulse, an imploded heated up 1 keV resulting in neutron increase 1000 times more than that without heating pulse. Details of implosion examined at Omega this type indirect...
We report on the characterization of specular reflection 50 fs laser pulses in intensity range 1017–1021 W cm−2 obliquely incident with p-polarization onto solid density plasmas. These measurements show that absorbed energy fraction remains approximately constant and second harmonic generation (SHG) achieves efficiencies 22±8% for intensities approaching 1021 cm−2. A simple model based relativistic oscillating mirror concept reproduces observed scaling, indicating this is dominant process...
An integrated experiment relevant to fast ignition . A Cu-doped deuterated polymer spherical shell target with an inserted hollow Au cone is imploded by a six-beam 900-J, 1-ns laser. 10-ps, 70-J laser pulse focused into the at time of peak compression. The flux high-energy electrons through material determined from yield CuKα fluorescence comparison Monte Carlo model. are estimated carry about 15% energy. Collisional and Ohmic heating modeled, effects shown be relatively unimportant....
We report on the first demonstration of passive all-optical plasma lensing using a two-stage setup. An intense femtosecond laser accelerates electrons in wakefield accelerator (LWFA) to 100 MeV over millimeter length scales. By adding second gas target behind initial LWFA stage we introduce robust and independently tunable lens. observe density dependent reduction electron beam divergence from an value 2.3 mrad, down 1.4 mrad (rms), when lens is operation. Such provides simple compact...
The spatial energy distributions of beams protons accelerated by ultrahigh intensity (>10(19)Wcm2) picosecond laser pulse interactions with thin foil targets are investigated. Using separate, low (<10(13)Wcm2) nanosecond pulses, focused onto the front surface target prior to arrival high pulse, it is demonstrated that proton beam profile can be actively manipulated. In particular, results obtained an annular distribution at focus presented, showing smooth a sharp circular boundary all...
Coherent wake emission is a unique source of extreme ultraviolet radiation and has been recently shown to provide the basis for intense attosecond light. Here we present novel scheme, supported by particle-in-cell simulations, demonstrating that enhancement spectral control coherent signal can be achieved modifying interaction plasma density ramp. Significant tunable harmonic verified experimentally, with factors >50 in relative increase narrow band harmonics at cutoff frequency.
Abstract The scaling of the flux and maximum energy laser-driven sheath-accelerated protons has been investigated as a function laser pulse in range 15–380 mJ at intensities 10 16 –10 18 W/cm 2 . duration target thickness were fixed 40 fs 25 nm, respectively, while focal spot size drive varied. Our results indicate that proton is dependent on diameter, primarily related to under conditions studied here. measurements show increasing by an order magnitude more than 500-fold increase observed...
We describe a laser-plasma platform for photon-photon collision experiments to measure fundamental quantum electrodynamic processes such as the linear Breit-Wheeler process with real photons. The has been developed using Gemini laser facility at Rutherford Appleton Laboratory. A wakefield accelerator and bremsstrahlung convertor are used generate collimated beam of photons energies hundreds MeV, that collide keV x-ray generated by heated plasma target. To detect pairs collisions, magnetic...
We present experimental results which show a laser polarization-dependent contribution to electron beam pointing jitter in wakefield accelerators (LWFAs). develop theoretical model for the polarization dependence terms of transverse dynamics trapped electrons, resonantly driven by bubble centroid oscillations. The latter are generated carrier wave phase evolution at self-steepened pulse front. In model, originates from shot-to-shot fluctuations envelope (CEP). is verified particle-in-cell...
MeV negative oxygen ions are obtained from a water spray target irradiated by high intensity (5 × 1019 W/cm2) and ultrashort (50 fs) laser pulses. Generation of is ascribed to electron-capture processes that the laser-accelerated high-energy positive ion experiences when it interacts with atoms in spray. This mechanism implies existence large number neutral atoms, which consistent indirect experimental evidence.