Fida Younus Khattak

• PhD
• Professor at Kohat University of Science and Technology

This study investigates how spin polarization, arising from spin mismatch between electron populations, influences the propagation of kinetic Alfvén waves (KAWs) in a low‐beta electron‐ion plasma. By analyzing the impact of spin‐polarized electron densities in distinct spin states, the research examines modifications to wave dispersion in both line...

This investigation explores the characteristics of electrostatic surface plasma waves within the framework of a spin‐polarized quantum plasma. Utilizing the spin‐polarized quantum hydrodynamic model and incorporating essential elements like Fermi pressure and Bohm potential, we derive the dispersion relation governing surface plasma waves at a plas...

The study explores the wave propagation characteristics of surface plasma waves in a semi-bounded plasma, incorporating the influence of spin polarization arising from spin mismatch. The formulated plasma model integrates the density correlation effect via Bohm's potential force, Fermi pressure employing Fermi-Dirac statistics, and the exchange pot...

Nonlinear propagation of a highly intense circularly polarized electromagnetic wave through a 3-component relativistic quantum plasma (RQP) is studied. The plasma is composed of relativistic degenerate electrons, dynamic-degenerate ions, and a beam of non-relativistic degenerate electrons. The relativistic degenerate electrons are modeled by a Klei...

In this paper, we have developed models based on Deep-Learning Neural Network (DNN) for accurately predicting lattice constants of half-Heusler alloys. A commercial software WIEN2k employing the Density Functional Theory (DFT) is first used to generate data of the lattice constants of 377 half-Heusler alloys for the training, testing and validation...

Three models based on the principle of Artificial Neural Network (ANN), predicting the lattice constants of full-Heusler alloys from the ionic radii, symbols of the constituent elements, and the combination of ionic radii and symbols are reported. The model predicted values of the lattice constants are compared with the theoretically simulated valu...

A Magnetized Relativistic Quantum Hydrodynamics (MRQH) model is used to study the behavior of low frequency electrostatic solitons in relativistic magnetized spin-polarized quantum plasma. The constituents of the plasma are inertia-less relativistic quantum electrons having concentration of both spin-up and spin-down species, and relativistic class...

The interaction of Circularly Polarized Electro-Magnetic (CPEM) waves with a 4-component relativistic quantum plasma is studied. The plasma constituents are: relativistic-degenerate electrons and positrons, dynamic degenerate ions, and Thomas-Fermi distributed electrons in the background. We have employed the Klein-Gordon equations for the electron...

A hydrodynamic model is employed to investigate the linear and non-linear propagation of Electrostatic Positron Acoustic Waves (EPAWs) in a 4-component relativistic-degenerate Electron-Positron-Ion (EPI) plasma. The plasma constituents are cold positrons, hot relativistic-degenerate electrons and positrons, and cold static ions in the background. T...

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 spindown ne# states and inertial classical ions. A two-dimensional plasma geometry is assumed having a uniform magnetic field, directed along the z-axis, i.e., B ¼ B0^...

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 of polarization for the Ne-like spectral lines 2s22p6 1S0 → 2s22p53s 1P1 (λ = 12.570 Å), 2s22p6 1S0 → 2s22p53s 3P...

Jets of energetic ions launched at laser-burnt-through foils represent an efficient tool for investigation of plasma interaction with solid surfaces (plasma-wall interaction, PWI) and for description of transient phenomena occurring close to the walls. Highly charged ions approaching the secondary target interpenetrate the near surface layer, colli...

A spectroscopic study of the He-α (1s21s0- ls2p 1p1) line emission (4749.73 eV) from high density plasma was conducted. The plasma was produced by irradiating Ti targets with intense (I ≈ l×l019 W/cm2), 400nm wavelength high contrast, short (45fs) p-polarized laser pulses at an angle of 45°. A line shift up to 3.4+1.0 eV (1.9±0.55 mÅ) was observed...

Recently the interest in relativistic quantum plasma is increasing primarily to understand the fundamentals of the plasma behaviour and its properties. Mathematical models used to investigate these plasma are still need to be matured. Especially, the relativistic quantum electron-ion plasma are modeled using the Klein-Gordon equation and the Dirac...

In this letter we present data comparing the yield of Cu K-α radiation for foils of differing thickness irradiated with a Ti:Sapphire laser generating 40 fs pulses at 800 nm and incident at 45°. At tight focus, the yields for all thicknesses are similar, whilst away from best focus there are clear differences. We discuss the origin of these similar...

In a proof of principle experiment using the LULI 100-TW laser facility ELFIE, we have demonstrated high spectral and spatial resolution of Kα volume radiation induced by energetic electrons generated by irradiating solid Cu targets with visible (0.53 µm) 350 fs laser pulses. Employing an x-ray spectrometer equipped with the spherically bent crysta...

We have studied a solid-to-plasma transition by irradiating Al foils with the FLASH free electron laser at intensities up to 10(16)  W/cm(2). Intense XUV self-emission shows spectral features that are consistent with emission from regions of high density, which go beyond single inner-shell photoionization of solids. Characteristic features of intra...

Aluminium targets were irradiated with 92 eV radiation from FLASH Free Electron Laser at DESY at intensities up to 1017 W/cm2 by focussing the beam on target down to a spot size of ~1 μm by means of a parabolic mirror. High resolution XUV spectroscopy was used to identify aluminium emission from complex hole-states. Simulations carried out with the...

Measurement of the dynamic properties of hydrogen and helium under extreme pressures is a key to understanding the physics of planetary interiors. The inelastic scattering signal from statically compressed hydrogen inside diamond anvil cells at 2.8 GPa and 6.4 GPa was measured at the Diamond Light Source synchrotron facility in the UK. The first di...

The FLASH XUV-free electron laser has been used to irradiate solid samples at intensities of the order 10(16) W cm(-2) at a wavelength of 13.5 nm. The subsequent time integrated XUV emission was observed with a grating spectrometer. The electron temperature inferred from plasma line ratios was in the range 5-8 eV with electron density in the range...

Optical Thomson scatter has been implemented as a diagnostic of laser ablated plumes under conditions relevant to pulsed laser deposition. The plumes have been generated with both KrF and second harmonic Nd:Yag laser radiation. Thomson scatter data with both spatial and temporal resolution has been collected giving both electron density and tempera...

We have studied the dynamics of warm dense Li with near-elastic x-ray scattering. Li foils were heated and compressed using shock waves driven by 4-ns-long laser pulses. Separate 1-ns-long laser pulses were used to generate a bright source of 2.96 keV Cl Ly- alpha photons for x-ray scattering, and the spectrum of scattered photons was recorded at a...

In this paper we describe experimental results on angularly resolved x-ray scatter from a sample of warm dense aluminium that has been created by double sided laser-driven shock compression. The experiment was carried out on the Central Laser Facility of the Rutherford Appleton Laboratory, using the VULCAN laser. The form of the angularly resolved...

We have carried out an optical Thomson scatter study of a KrF laser-ablated Mg plume. The evolution of the electron temperature and density at distances 2–5 mm from the target surface has been studied. We have observed that the electron density falls more rapidly than the atomic density and believe that this is a result of rapid dielectronic recomb...

High-energy decay channels of the Al Lyman-β satellite have been observed in X-ray emission from highly ionized plasma jets created by intense laser irradiation of aluminium foil targets. Atomic structure calculations show that the Lyman β satellite emission consists from six emission groups close to the He-like Al 1s2-1s4p (Heγ) and 1s2-1s5p (Heδ)...

Saturable absorption is a phenomenon readily seen in the optical and infrared wavelengths. It has never been observed in core-electron transitions owing to the short lifetime of the excited states involved and the high intensities of the soft X-rays needed. We report saturable absorption of an L-shell transition in aluminium using record intensitie...

We report on the x-ray absorption of Warm Dense Matter experiment at the FLASH Free Electron Laser (FEL) facility at DESY. The FEL beam is used to produce Warm Dense Matter with soft x-ray absorption as the probe of electronic structure. A multilayer-coated parabolic mirror focuses the FEL radiation, to spot sizes as small as 0.3μm in a ∼15fs pulse...

An attempt was made to use the ASTRA laser system at the Rutherford Appleton Laboratory to generate an X-ray Laser (XRL) via an inner-shell photoionisation pumping scheme, in which a laser produced plasma acts as an x-ray flash-lamp to excite electrons from the inner-shell of the lasant material and hence generate a population inversion. The rise t...

We have used the XUV FLASH laser at DESY to irradiate solid targets with intense XUV pulse at 13.5nm and ~1016 Wcm−2. XUV emission spectroscopy using a grating spectrometer has been used to observe both continuum radiation and line emission from Al IV. We present some preliminary results that indicate time integrated temperatures of below 20eV whil...

The analysis of the radiative properties of plasmas created by XUV and X-ray free electron laser radiations provides a tremendous challenge to researchers to investigate matter under extreme conditions. In the present work we report about the theoretical analysis of the radiation emission of Al heated by the interaction of 10 fs focused (1 μm) free...

One of the grand challenges of contemporary physics is understanding strongly interacting quantum systems comprising such diverse examples as ultracold atoms in traps, electrons in high-temperature superconductors and nuclear matter. Warm dense matter, defined by temperatures of a few electron volts and densities comparable with solids, is a comple...

We have performed time-resolved x-ray scattering measurements in the warm dense matter regime at the LULI 2000 laser facility (Ecole Polytechnique, France). The laser-driven shocked CH samples were probed with 30ps, 8keV Cu Kalpha radiation, delayed with respect to the shock propagation. The angularly resolved scattered x-ray signal, collected over...

Raman satellites have been observed in the scattering of a Nd:YAG laser (532nm) from a laser-ablated Mg plasma plume. We identify them as originating from transitions between the fine-structure components of the metastable 3s3pP0,1,23 level of Mg. We have calculated the cross sections for Raman and Rayleigh scattering from the metastable state. Com...

We have investigated the angular variation in elastic x-ray scattering from a dense, laser-shock-compressed aluminum foil. A comparison of the experiment with simulations using an embedded atom potential in a molecular dynamics simulation shows a significantly better agreement than simulations based on an unscreened one-component plasma model. Thes...

We have performed spectrally and angularly resolved x-ray scattering measurements in solid density plasmas produced by shock compression with a high power laser. The experiments have been performed at the VULCAN laser facility and at the LULI2000 facility. We have investigated warm and dense low-Z materials with particular regards to the regime whe...

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 temperature was found to decay with the expected Te∝t−1 dependence. However, we have found the electron density to have a time dependence ne∝t−4.95 which can be expla...

Ultra-fast material dependent radiative heating of dense matter was observed at the Vulcan 100 TW laser facility at RAL (UK). These processes are driven by the transport of fast electrons which isochorically heat the solid at temperatures where radiative processes may become important. The peak laser intensity on target was ˜10^19 W/cm-2 for irradi...

Dense titanium plasma has been heated to an electron temperature up to 1300 eV with a 100 TW, high intensity short-pulse laser. The experiments were conducted using Ti foils 5 m thick sandwiched between layers of either aluminum 1 or 2 m thick or plastic 2 m thick to prevent the effects of prepulse. Targets of two different sizes, i.e., 250 250 m 2...

A novel wide angle spectrometer has been implemented with a highly oriented pyrolytic graphite crystal coupled to an image plate. This spectrometer has allowed us to look at the energy resolved spectrum of scattered x rays from a dense plasma over a wide range of angles (approximately 30 degrees ) in a single shot. Using this spectrometer we were a...

We report spectrally resolved X-ray scattering data from shock compressed foils illustrating the feasibility of X-ray Thomson scattering experiment on a sub-kilo joule laser system. Sandwich targets consisting of CH/Al/CH were shock compressed using [similar]1 ns laser pulses. Separate 270 ps laser pulses were used to generate an intense source of...

We report on measurements made of the levels of stimulated Raman and Brillouin scattering in a long-scalelength preformed plasma. The effectiveness of a random phase plate and an induced spatial incoherence system to suppress these instabilities by reducing the coherence of the laser beam have been studied. It has been found that both these methods...

The authors present experimental results showing how the use of a high contrast femtosecond laser system allows better optimization of Kalpha emission from a Cu target. The shorter scale-length preformed plasma is better optimized for resonance absorption of the laser light when the laser is moved away from best focus. The experimental data show a...

We report on a study comparing absolute K-or. yield from Ti foils measured with a calibrated system of an X-ray CCD coupled to a curved LiF Von-Hamos crystal spectrometer to the difference in the signals measured simultaneously with two similar photodiodes fitted with two different filters. Our data indicate that a combination of photodiodes with d...

This article discusses the design of a novel time resolved von Hamos Bragg spectrometer to provide spectra in the region around the titanium K-alpha and He-alpha lines. The instrument consists of a highly oriented pyrolitic graphite mosaic crystal coupled to a picosecond x-ray streak camera. Measurements of the time dependent behavior from Ti foils...

Ti Kα emission yields from foils irradiated with ∼45 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 with the cross section for K-shell ionization of Ti and the Bethe-Bloch stopping power equation for electrons. The p...

We have used the ASTRA laser facility to irradiate Ti foils with 45-fs 400 nm laser pulses at irradiances up to . We have observed both thermal line radiation, in the form of the He-like 1s2-1s2p transitions (He-α), and the K-α emission line. We have noted that the efficiency of K-α production is in excess of 2×10-4 and thus compares well with usin...

We have studied the heating to Te>100 eV of tamped Ti foil targets at near solid density, conditions which are found in inertial confinement fusion and laboratory astrophysics plasmas. The experiments were conducted at the Vulcan Laser Facility at the Rutherford Appleton Laboratory (UK) using a 100 J, 1.5 ps laser beam focused to a 10 micron spot o...

We review the potential of x-ray scattering as a dense plasma diagnostic and present data taken from experiments in which x-ray scattering from dense plasmas is developed as a diagnostic tool. In one type of experiment the scattered photons are detected as a function of angle using direct detection onto a CCD chip. Such experiments are designed pri...

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 a frequency doubled Ti:Sapphire laser. By varying the beam spot, the intensity on target was varied from 1015 W/cm2 to 1019 W/cm2. At best focus, low density “smoked” Ti targets yield ∼ 20 times more He-α than the fo...

We present a study of He-like 1s(2)-1s2p line emission from solid and low-density Ti targets under similar or equal to 45 fs laser pulse irradiation with a frequency doubled Ti: Sapphire laser. By varying the beam spot, the intensity on target was varied from 10(15) W/cm(2) to 10(19) W/cm(2). At best focus, low density "smoked" Ti targets yield sim...

We have studied the emission of Kalpha radiation from Ti foils irradiated with ultrashort (45 fs) laser pulses. We utilized the fundamental (800 nm) light from a Ti:sapphire laser on bare foils and foils coated with a thin layer of parylene E (CH). The focusing was varied widely to give a range of intensities from approximately 10(15) - 10(19) W cm...

The authors present an analysis of an X-ray laser Thomson scatter experiment attempted at the Rutherford-Appleton Laboratory. Although the experiment was for technical reasons not completed, an analysis of the feasibility is instructive. X-ray lasers are potentially a useful source for this type of experiment as they have high brightness, short pul...

A study of the Kagr radiation emitted from Ti foils irradiated with intense, ~0.2 J, 67 fs, 800 nm laser pulses, scanning a range of intensities (~1015 1018 W cm-2), is reported. The brightness of single-shot Kagr line emission from the front of the targets is recorded. The yield from bare titanium (Ti) is compared to that from plastic (parylene-E)...

Photon yields for the 1s2–1s2p (He-α) transition of He-like ions have been measured for laser irradiated, thin foils of Ti, V and Fe. The laser pulses were of 0.527 μm wavelength and of either 80 or 300 ps duration. The data shows significant shot-to-shot variation but the Ti data is broadly consistent with previous results. In this work, we extend...

Summary form only given, as follows. A series of experiments have been carried out at the Rutherford-Appleton laboratory to investigate X-ray scattering from laser produced plasmas. Most experiments shave been based on Rayleigh scattering from bound electrons and are sensitive to ion-ion correlations which lead to a scattering structure factor with...

The current sheath behavior in a small 3 kJ plasma focus device, in the presence of a target placed downstream of the anode is investigated. The voltage signal and the sequential bursts of neutrons give a clear indication of the occurrence of the sequential focusing.

A high brightness, Raman amplified KrF laser has been used to irradiate solid targets with 12 ps laser pulses at intensities above 10 exp 15 W/sq cm without the presence of a preformed plasma caused by low level amplified spontaneous emission prepulse. Time-resolved X-ray spectroscopy of the K-shell emission from aluminum was used to infer electron...

Recent progress in multilayered mirror technology has allowed the developments of novel imaging systems for probing of high density plasmas in the soft x‐ray regime. The experimental system described here basically consists of a spherical multilayered mirror which reflects a narrow band (∓5 eV) of soft x‐ray radiation in the 50 to 200 eV energy reg...

The use of rectangular-element random phase plates to generate a line focus is described. Photographic records of the resultant focus are presented and compared with theoretical calculations made by using an interference code. Good agreement is found. The code is used to investigate possible design modifications to produce a more square-topped line...

The first high-resolution (spatial and temporal) 2D images of the density region close to the ablation surface of laser-irradiated targets are obtained using a novel x-ray imaging technique. These show that laser intensity nonuniformities imprint themselves onto the cold target surface, even if these exist only on short ~=10 ps time scales as is th...

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 using the induced spatial incoherence (ISI) technique. The first observation of the occurrence of thermal whole-beam self-focusing with ISI laser light is pres...

Several basic processes occurring during the interaction of laser irradiation with matter have been investigated by using the high power laser systems of the SERC Central Laser Facility. The main effort of the recent research concentrated on ICF related studies with improved laser illumination uniformity generated by Random Phase Plate (RPP) Arrays...

A novel and simple XUV imaging technique using a laser-produced plasma source is described. A spatial resolution of better than 0.8 μm is demonstrated.

Using vacuum deposition methods a range of micro-structured coatings of differing metallic elements have been fabricated for use on high power laser experiments in the CLF. Studies were carried out to determine how a range of process conditions affect the coating micro-structure and the studies were used to design a dedicated vacuum coating plant t...

1 Introduction In recent years, spectrally resolved X-ray scattering has been developed for the probing of dense plasmas [1-6] . This has been motivated by the desire to reproduce the significant success of Thomson scattering in the optical regime for lower density plasmas. So far this technique has been successful in diagnosing electron temperatur...

We present a study of $\chem{He}$-like 1$s^2$-1$s$2$p$ line emission from solid and low-density $\chem{Ti}$ targets under $\simeq 45\un{fs}$ laser pulse irradiation with a frequency doubled $\chem{Ti}$:Sapphire laser. By varying the beam spot, the intensity on target was varied from $10^{15}\un{W/cm^2}$ to $10^{19}\un{W/cm^2}$. At best focus, low d...

Journal article

Journal article Temporary entry (new)