A5041780717- Physics of Superconductivity and Magnetism
- High-pressure geophysics and materials
- Semiconductor Lasers and Optical Devices
- Photonic and Optical Devices
- Laser-Plasma Interactions and Diagnostics
- Laser-induced spectroscopy and plasma
- Optical Network Technologies
- Superconductivity in MgB2 and Alloys
- Advanced Condensed Matter Physics
- Superconducting Materials and Applications
- Ion-surface interactions and analysis
- Ferroelectric and Piezoelectric Materials
- Muon and positron interactions and applications
- Multiferroics and related materials
- Iron-based superconductors research
- Laser-Matter Interactions and Applications
- Nuclear Materials and Properties
- Acoustic Wave Resonator Technologies
- ZnO doping and properties
- Metal and Thin Film Mechanics
- Thermal Expansion and Ionic Conductivity
- Fusion materials and technologies
- Semiconductor Quantum Structures and Devices
- Advancements in Battery Materials
- Magnetic and transport properties of perovskites and related materials
University of Engineering & Management
2020-2023
Institute of Engineering
2022
Maulana Abul Kalam Azad University of Technology, West Bengal
2017
Variable Energy Cyclotron Centre
2005-2016
Rutherford Appleton Laboratory
2006-2011
Manipur University
2011
S.N. Bose National Centre for Basic Sciences
2011
Bhabha Atomic Research Centre
2011
Science and Technology Facilities Council
2009
University of Wales
2003-2005
We present measurements of a magnetic reconnection in plasma created by two laser beams (1 ns pulse duration, $1\ifmmode\times\else\texttimes\fi{}{10}^{15}\text{ }\text{ }\mathrm{W}\text{ }{\mathrm{cm}}^{\ensuremath{-}2}$) focused close proximity on planar solid target. Simultaneous optical probing and proton grid deflectometry reveal high velocity, collimated outflowing jets 0.7---1.3 MG fields at the focal spot edges. Thomson scattering from layer are consistent with electron temperatures...
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.
Laser-driven magnetic reconnection is investigated using proton deflectometry. Two laser beams of nanosecond duration were focused in close proximity on a solid target to intensities I∼1×1015 W cm−2. Through the well known ∇ne×∇Te mechanism, azimuthal fields are generated around each focal spot. During expansion two plasmas, oppositely oriented field lines brought together resulting region between spots. The spatial scales and plasma parameters consistent with proceeding due Hall mechanism....
Measurements of the bidirectional plasma jets that form at surface a solid target during laser-generated driven magnetic reconnection are presented. Resistivity enhancement least 25× classical Spitzer value is required when applying Sweet–Parker model to reconcile experimentally observed time scale. Analytic calculations show fast model, which includes priori effects microturbulent resistivity enhancement, better reproduces experimental observations.
Experiments where a laser-generated proton beam is used to probe the megagauss strength self-generated magnetic fields from nanosecond laser interaction with an aluminum target are presented. At intensities of 10(15) W cm(-2) and under conditions significant fast electron production strong heat fluxes, mean-free-path long compared temperature gradient scale length hence nonlocal transport important for dynamics field in plasma. The hot flux transports away focal region through Nernst effect...
In this letter we report on the direct density measurement in a shock compressed aluminum target using hard x-ray radiography. Experimental data employing molybdenum Kα source at 17.5keV, generated with short pulse laser are presented. High spatial resolution was obtained thanks to new design for backlighter geometry. Density values deduced from radiography compared predictions hydrodynamic simulations, which have been calibrated order reproduce velocities measured rear-side self-emission...
During the last ten years, ability of high power lasers to generate energy density shocks has made them a reliable tool study extreme states matter. These matter are relevant in many important physics areas such as astrophysics, planetology and ICF physics. Here, we present some representative studies performed by using driven laser shock: melting iron at pressures for geophysics, developments new techniques measure highly compressed radiative shock.
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...
We have investigated the fluctuation induced conductivity (FIC) of two high-Tc superconductors (HTSC) namely Bi2Sr2Ca1Cu2O8+δ and Y1−xCaxBa2Cu3Oy. The effective medium theory is used to formulate Aslamazov–Larkin type equations for these polycrystalline superconductors. For three dimensional case temperature exponent remains unaltered since both exponents ab plane c direction FICs in crystal are same. But situation more complex where counterparts different dependencies. FIC evaluated...
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.
In this paper we report on the radiography of a shock-compressed target using laser produced proton beams. A low-density carbon foam was shock compressed by long pulse high-energy The front transversally probed with beam in interaction high intensity gold foil. We show that from data, density profile shocked can be deduced Monte Carlo simulations. By changing delay between and short beams, could probe different plasma conditions structures, demonstrating details steep gradient resolved. This...
The stability of the polarization-resolved (PR) light output a commercial vertical-cavity surface-emitting laser (VCSEL) has been studied with and without presence external optical injection in master-slave configuration. Pulsations PR are observed solitary at certain bias current. It here for first time that can stabilize polarization VCSEL operating pulsation regime.
The scaling behavior of the Portevin--Le Chatelier (PLC) effect was studied by deforming an $\mathrm{A}\mathrm{l}\mathrm{\text{\ensuremath{-}}}2.5%\mathrm{M}\mathrm{g}$ alloy for a wide range strain rates. To reveal exact nature, time series data true stress versus time, obtained during deformation, were analyzed two complementary methods: finite variance method and diffusion entropy analysis. From these analyses we could establish that, in entire span rates, PLC showed Levy-walk property.