A5041376756- Laser-Plasma Interactions and Diagnostics
- Laser-induced spectroscopy and plasma
- Atomic and Molecular Physics
- High-pressure geophysics and materials
- Dust and Plasma Wave Phenomena
- Advanced X-ray Imaging Techniques
- Cold Atom Physics and Bose-Einstein Condensates
- Ion-surface interactions and analysis
- Diamond and Carbon-based Materials Research
- Laser Material Processing Techniques
- Laser-Matter Interactions and Applications
- Ionosphere and magnetosphere dynamics
- X-ray Spectroscopy and Fluorescence Analysis
- Laser Design and Applications
- Plasmonic and Surface Plasmon Research
- Machine Learning in Materials Science
- Particle Accelerators and Free-Electron Lasers
- Heusler alloys: electronic and magnetic properties
- Phase Equilibria and Thermodynamics
- Solid State Laser Technologies
- Engineering Applied Research
- Theoretical and Computational Physics
- Spectroscopy and Laser Applications
- Advanced Thermoelectric Materials and Devices
- Gas Dynamics and Kinetic Theory
Pak-Austria Fachhochschule: Institute of Applied Sciences and Technology
2022-2024
COMSATS University Islamabad
2024
Kohat University of Science and Technology
2011-2022
Laboratoire de Physique des Plasmas
2012
École Polytechnique
2012
Laboratoire pour l'utilisation des lasers intenses
2012
Centre National de la Recherche Scientifique
2012
CEA Paris-Saclay
2012
Commissariat à l'Énergie Atomique et aux Énergies Alternatives
2012
University of California, Los Angeles
2010
The first high-resolution (spatial and temporal) 2D images of the density region close to ablation surface laser-irradiated targets are obtained using a novel x-ray imaging technique. These show that laser intensity nonuniformities imprint themselves onto cold target surface, even if these exist only on short \ensuremath{\simeq}10 ps time scales as is case with beam smoothed by induced spatial incoherence. This phenomenon interpreted in terms poor thermal smoothing under conditions...
We have studied a solid-to-plasma transition by irradiating Al foils with the FLASH free electron laser at intensities up to ${10}^{16}\text{ }\text{ }\mathrm{W}/{\mathrm{cm}}^{2}$. Intense XUV self-emission shows spectral features that are consistent emission from regions of high density, which go beyond single inner-shell photoionization solids. Characteristic intrashell transitions allowed us identify Auger heating electrons in conduction band occurring immediately after absorption energy...
Dense titanium plasma has been heated to an electron temperature up 1300eV with a 100TW, high intensity short-pulse laser. The experiments were conducted using Ti foils (5μm thick) sandwiched between layers of either aluminum (1 or 2μm plastic (2μm prevent the effects prepulse. Targets two different sizes, i.e., 250×250μm2 and 1×1mm2 used. Spectral measurements inner-shell emission, in region 4and5keV, taken from front-side (i.e., laser illuminated side) target. data show large shifts Kα...
A separated spin evolution quantum hydrodynamics model is employed to study low frequency electrostatic waves in plasmas having inertia-less degenerate electrons with spin-up ne↑ and spin-down ne↓ states inertial classical ions. two-dimensional plasma geometry assumed a uniform magnetic field, directed along the z-axis, i.e., B=B0ẑ. Zakharov-Kuznetsov (ZK) type equation derived for potential via Reductive Perturbation Technique. The parametric role of density polarization ratio κ...
A high brightness, Raman amplified KrF laser has been used to irradiate solid targets with 12 ps pulses at intensities above ${10}^{15}$ W/${\mathrm{cm}}^{2}$ without the presence of a preformed plasma caused by low level spontaneous emission prepulse. Time-resolved x-ray spectroscopy K-shell from aluminum was infer electron densities in excess ${10}^{23}$ ${\mathrm{cm}}^{\mathrm{\ensuremath{-}}3}$ temperatures several hundred electronvolts.
We have studied the emission of Kalpha radiation from Ti foils irradiated with ultrashort (45 fs) laser pulses. utilized fundamental (800 nm) light a Ti:sapphire on bare and coated thin layer parylene E (CH). The focusing was varied widely to give range intensities approximately 10(15) - 10(19) W cm(-2). Our results show conversion efficiency energy 10(-4) at tight focus for both types targets. In addition, targets exhibited strong secondary peaks large defocus, which we believe are due...
We have investigated the angular variation in elastic x-ray scattering from a dense, laser-shock-compressed aluminum foil. A comparison of experiment with simulations using an embedded atom potential molecular dynamics simulation shows significantly better agreement than based on unscreened one-component plasma model. These data illustrate, experimentally, importance screening for dense static structure factor.
We have carried out an optical Thomson scatter study of a KrF laser-ablated Mg plume. The evolution the electron temperature and density at distances 2–5mm from target surface has been studied. observed that falls more rapidly than atomic believe this is result rapid dielectronic recombination. A comparison profile with simple hydrodynamic modeling indicates there strong absorption laser in plasma vapor above target, probably due to photoionization. also conclude isothermal model expansion...
A spectroscopic study of the He-α (1s2 1s0 - ls2p 1p1) line emission (4749.73 eV) from high density plasma was conducted. The produced by irradiating Ti targets with intense (I ≈ l×l019 W/cm2), 400nm wavelength contrast, short (45fs) p-polarized laser pulses at an angle 45°. shift up to 3.4+1.0 eV (1.9±0.55 mÅ) observed in line. width resonance FWHM measured be 12.1±0.6 (6.7±0.35 mÅ). For comparison, we looked into same spectral target reduced intensities (≈1017 W/cm2): a only 1.8+1.0...
The study explores the wave propagation characteristics of surface plasma waves in a semi-bounded plasma, incorporating influence spin polarization arising from mismatch. formulated model integrates density correlation effect via Bohm's potential force, Fermi pressure employing Fermi-Dirac statistics, and exchange potential. These factors are considered spin-polarized form interconnected through index κ. We derive dispersion relation for waves, delineating features configured mode. Our...
Ti $K\ensuremath{\alpha}$ emission yields from foils irradiated with $\ensuremath{\sim}45\phantom{\rule{0.3em}{0ex}}\mathrm{fs}$, $p$-polarized pulses of a frequency-doubled Ti:sapphire laser are presented. A simple model invoking vacuum heating to predict absorption and hot electron temperature was coupled the cross section for $K$-shell ionization Bethe-Bloch stopping power equation electrons. The peak predicted in generally good agreement experiment. This contrasts strongly previous work...
Photon yields for the 1s2–1s2p (He-α) transition of He-like ions have been measured laser irradiated, thin foils Ti, V and Fe. The pulses were 0.527 μm wavelength either 80 or 300 ps duration. data shows significant shot-to-shot variation but Ti is broadly consistent with previous results. In this work, we extend results to include, new elements, longer pulse lengths emission from both surfaces foils. We compare our simulations using a hydrodynamic code collisional radiative model.
The propagation of an intense electromagnetic pulse in a large underdense plasma has been investigated using spatially and temporally incoherent laser light. Spatial incoherence was obtained the induced spatial (ISI) technique. first observation occurrence thermal whole-beam self-focusing with ISI light is presented. Thermal imaging multiframe x-ray camera (140 ps gate time) used to record characteristics interaction beam through plasma. A direct measurement growth length made.
We report on measurements made of the levels stimulated Raman and Brillouin scattering in a long-scalelength preformed plasma. The effectiveness random phase plate an induced spatial incoherence system to suppress these instabilities by reducing coherence laser beam have been studied. It has found that both methods give rise significant reduction under experimental conditions.
We have studied the dynamics of warm dense Li with near-elastic x-ray scattering. foils were heated and compressed using shock waves driven by 4-ns-long laser pulses. Separate 1-ns-long pulses used to generate a bright source 2.96 keV Cl Ly-$\ensuremath{\alpha}$ photons for scattering, spectrum scattered was recorded at scattering angle $120\ifmmode^\circ\else\textdegree\fi{}$ highly oriented pyrolytic graphite crystal operated in von Hamos geometry. A variable delay between heater...
We report spectrally resolved X-ray scattering data from shock compressed foils illustrating the feasibility of Thomson experiment on a sub-kilo joule laser system. Sandwich targets consisting CH/Al/CH were using ∼1 ns pulses. Separate 270 ps pulses used to generate an intense source Ti-He-α (1s 2 -1s2p 1 P) radiation which was as probing 4.75 keV photons. The spectrum scattered photons recorded at angle 82° with CCD fitted spectrometer PET crystal in von-Hamos geometry. Although spectral...
A novel wide angle spectrometer has been implemented with a highly oriented pyrolytic graphite crystal coupled to an image plate. This allowed us look at the energy resolved spectrum of scattered x rays from dense plasma over range angles (approximately 30 degrees ) in single shot. Using this we were able observe temporal evolution angular scatter cross section laser shocked foil. type may also be useful investigations x-ray line transfer laser-plasmas experiments.
We present a study of He-like 1s2-1s2p line emission from solid and low-density Ti targets under ≃ 45 fs laser pulse irradiation with frequency doubled Ti:Sapphire laser. By varying the beam spot, intensity on target was varied 1015 W/cm2 to 1019 W/cm2. At best focus, low density "smoked" yield ∼ 20 times more He-α than foil when irradiated at an angle 45° s-polarized pulses. The duration smoked targets, measured fast streak camera, similar that foils.
We have obtained density and temperature informations on an expanding KrF laser-ablated magnesium plume via optical Thomson scatter with a frequency doubled Nd:YAG laser. The electron was found to decay the expected Te∝t−1 dependence. However, we time dependence ne∝t−4.95 which can be explained by strong recombination processes. also observed atomic Raman satellites originating from transitions between different angular momentum levels of metastable P03 term in MgI.
The authors present experimental results showing how the use of a high contrast femtosecond laser system allows better optimization Kα emission from Cu target. shorter scale-length preformed plasma is optimized for resonance absorption light when moved away best focus. data show central peak at tight focus with strong secondary peaks large offset. these in much reduced hard x-ray background and should lead to pulses than
In a proof of principle experiment using the LULI 100-TW laser facility ELFIE, we have demonstrated high spectral and spatial resolution Kα volume radiation induced by energetic electrons generated irradiating solid Cu targets with visible (0.53 µm) 350 fs pulses. Employing an x-ray spectrometer equipped spherically bent crystal quartz (502) image plate, single shot Cu-Kα radiation was recorded in first-order reflection allowing for geometrical mapping emission hot down to 30 µm. The...
Soft x-ray emission from CuXX L-shell lines emitted by a dense X-pinch plasma have been investigated with high-resolution curved Bragg crystals at different angles of orientation. Single shot time integrated spectra show clear evidences polarization for the Ne-like spectral 2s22p6 1S0 → 2s22p53s1P1 (λ = 12.570 Å), 2s22p53s3P1 12.8277 Å). The variation intensity ratio these two well-separated is discussed in view its application suprathermal electron characterization under real experimental...
We review the potential of x-ray scattering as a dense plasma diagnostic and present data taken from experiments in which plasmas is developed tool. In one type experiment scattered photons are detected function angle using direct detection onto CCD chip. Such designed primarily to observe static ion–ion structure factor, expected dominate for moderate high Z at few electronvolts temperature. second we have used curved crystal spectrally resolved fixed angle. This was dynamical factor plasma.