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Elnaz Yazdani

AmirKabir University Of Technology, Physics, Graduate Student

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Homi Bhabha National Institute

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Papers by Elnaz Yazdani

Parametric study of ultra-intense laser interaction with uniform and nano-porous near-critical plasmas

AIP Advances, 2020

Paper published as part of the special topic on Chemical Physics, Energy, Fluids and Plasmas, Mat... more Paper published as part of the special topic on Chemical Physics, Energy, Fluids and Plasmas, Materials Science and Mathematical Physics ARTICLES YOU MAY BE INTERESTED IN Generation of energetic ring-shaped ion beam from relativistic Laguerre-Gaussian laser pulse interacting with micro-structure targets Physics of Plasmas 27, 053105 (2020);

Random laser of rhodamine 6G dye solution embedded with ZnO microstructures

Optics and Photonics Society of Iran, 2019

In this study, Zinc oxide microstructures with high porosity and surface area to volume ratio in ... more In this study, Zinc oxide microstructures with high porosity and surface area to volume ratio in order to the light localization has been selected and synthesized. Characterization measurements; such as SEM, XRD and EDAX has been carried out on the structures. Random laser emission with coherence feedback from rhodamine6G solution embedded ZnO microstructures and effect of the pump energy on spectrum emission variation have been investigated.

Comprehensive study of anomalous hysteresis behavior in perovskite-based solar cells

Perovskite solar cells (PSCs) have shown remarkable progress with the rapid increase in power con... more Perovskite solar cells (PSCs) have shown remarkable progress with the rapid increase in power conversion efficiency to reach 25.7% over the last few years. However, it is difficult to precisely determine the energy conversion efficiency for PSC, because of anomalous current density- voltage (J-V) hysteresis. Normal J-V hysteresis has been reported in many papers, where the backward scan (BS) performance is higher than the forward scan (FS) one. In this work, using Drift-Diffusion Modeling (DDM), normal hysteretic behavior associated with ion migration with different scanning rates, pre-bias voltages, and charge-carrier mobility is studied. In addition, the inverted J − V hysteresis by modification of the simulation model, where anions and cations flux towards the transport layers and are accumulated simultaneously on both sides, is achieved. It is also found that the flux parameter values (gae and gch) play a critical role in the reduction of inverted hysteresis and the efficiency e...

Mode-controlled random laser assisted by stimulated Raman scattering

Optics Communications, 2021

Abstract In this study, a reproducible and stable mode random laser is fabricated from Rhodamine ... more Abstract In this study, a reproducible and stable mode random laser is fabricated from Rhodamine 6G dye-containing ZnO@C-N microstructures by using an approach based on the coupling of the stimulated Raman scattering effect and random lasing process. Under intense pump energy, the Raman peaks of Rhodamine 6G work as seeds, and multiple elastic scattering in the disordered medium will amplify them. On the other hand, ZnO@C-N porous microstructures with plenty of nanosheets and high surface area effectively act as scatterer centers in providing strong multiple elastic scattering. So that, the strong feedback from nanosheets of the individual microstructures, allows the system to operate at a low concentration of scatterers (as low as 2mg/ml). Moreover, the enhancement of Raman modes as a function of the pump pulse energies and scatterers concentrations is examined. The results show that the Raman modes after manifestation are stable and reproduce well from pulse-to-pulse pump energy variation. Our findings introduce a new approach to tune the wavelength of random lasers for real applications and also enable the laser mode selection.

Target Nano-particles size effect on the laser proton acceleration in the TNSA mechanism

On Nonlinear Evolutions of the Intense, Short Laser Pulse in the Under-Dense Plasma

arXiv: Plasma Physics, 2016

Nonlinear evolutions of an ultra-intense, short laser pulse due to the wake excitation inside the... more Nonlinear evolutions of an ultra-intense, short laser pulse due to the wake excitation inside the plasma are studied by means of detailed Particle-In-Cell (PIC) simulations and comprehensive analyses. Pulse lengths both longer and shorter than the plasma wavelength are considered. It is turned out that the system shows adiabatic behavior as long as the plasma evolves very slowly in the Pulse Co-Moving (PCM) frame due to the ignorable radiation back-reactions. A sophisticated treatment of the adiabatic regime is presented, based on the proper application of the local conservation laws in the PCM frame in conjunction with the Lorentz transformations. In this context, equations for the overall pulse evolutions are reduced into a single equation in terms of the global pulse group-velocity. Due to the proven equality between the local phase velocities of the plasma wave and the radiation, anomalies are observed in this regime, in the global group velocity and the plasma dispersion. The g...

Crystal morphology effect on optical properties of halide Perovskite thin films

Optics and Photonics Society of Iran, 2019

Optical response of CH3NH3PbBr3 perovskite thin films to the variations of procures stoichiometry

Optics and Photonics Society of Iran, 2020

In addition to the successful use of organic-inorganic hybrid perovskite materials in photovoltai... more In addition to the successful use of organic-inorganic hybrid perovskite materials in photovoltaics, these materials have been shown significant role in perovskite based light emitting diodes development. In this work, the effect of the variation precursor stoichiometry of CH3NH3PbBr3 perovskite on structure, morphology and optical response of thin films by using of ،XRD ،UV-Vis ،PL and TRPL characteristic techniques has been studied. The results revealed that, the crystallinity and morphology of perovskite thin films for precursor’s ratio of 1/25:1 compare to the case of 1:1 is improved and the radiative recombination rate of the carrier and photoluminescence intensity is increased.

Theory of the ultra-intense short-pulse laser interaction with under-dense plasma

A comprehensive theory is proposed to describe the propagation and absorption of ultra-intense, s... more A comprehensive theory is proposed to describe the propagation and absorption of ultra-intense, short laser pulse through the under-dense plasma. The kinetic aspects of plasma are fully incorporated using extensive particle-in-cell (PIC) simulations. It is turned out that the plasma behavior is characterized by both its density and the ratio of the pulse length to the plasma wavelength. According to exact analyses and direct simulation evidences, at ultra-low densities the laser pulse is adiabatically depleted (absorbed) by the wake excitation. And the depletion is accompanied by the overall radiation red-shift. At these densities, for pulse lengths larger than the plasma wavelength the Raman type scatterings also occur without causing instability. When the plasma density grows toward the critical density, a completely new regime appears with the main character of highly unsteady light propagation. Here, based on analyses and simulations, the radiation pressure induced wave breaking...

The effect of solvent on random laser of Rhodamine 6G dye solution with ZnO@C-N microstructures

Optics and Photonics Society of Iran, 2020

In this study, Carbon and Nitrogen doped Zinc oxide microstrcturess as scatterer centers in Rhoda... more In this study, Carbon and Nitrogen doped Zinc oxide microstrcturess as scatterer centers in Rhodamine 6G dye as gain media has been selected and synthesized. The existence of the sheetlike structures in ZnO@C-N sample due to the Carbon and Nitrogen dopants, is improves the scatterers morphologies .Later on, the random laser emission for two independent samples for the same concentration of gain media and scatterer centers, with different solvents in order to evaluating the effect of the solvent on output spectrum, have been studied. The results show higher polarity of solvent leads increasing the red shift and decreasing the spectrum intensity and does not have any significant effect on localization threshold and output modes.

Short Intense Laser Pulse Depletion and Scattering in Under-Dense Plasma

Nonlinear evolutions of an ultra-intense, short laser pulse due to the wake excitation inside the... more Nonlinear evolutions of an ultra-intense, short laser pulse due to the wake excitation inside the plasma are studied by means of detailed particle-in-cell simulations and comprehensive analyses. Pulse lengths both longer and shorter than the plasma wavelength are considered. A new adiabatic regime of the interaction is identified in connection with the quasi-static being of the plasma in the pulse commoving frame. This situation occurs when radiation back-reactions are ignorable in the commoving frame against the measured high plasma momentum. By formulating this regime in terms of the local conservation laws, we calculate the overall pulse depletion and more importantly the global pulse group velocity. The outcome for the group velocity shows non-explicit density dependency and, strangely, remains above the linear value over a long time period. Further, we examine the model adequacy at different applied parameters via comparison with simulations. It is turned out that for pulse len...

Narrow-band random Raman lasing from Rhodamine 6G assisted by cascaded stimulated Raman scattering effect

Scientific Reports, 2021

This study reports the first experimental observation of cascaded stimulated Raman scattering (SR... more This study reports the first experimental observation of cascaded stimulated Raman scattering (SRS) generation in a colloidal disordered medium. Generation of the cascaded effect requires both a high Raman gain and pump power in the disordered medium. Here, to extend effective path lengths of photons into the Raman gain medium for producing additional SRS processes, ZnO microspheres with abundant nano-protrusions as suitable scattering centers are proposed. It is explained that nano-protrusions on the surface of the spheres can act as nano reflectors and significantly provide potent feedback in the disordered system. This provided feedback via nano-protrusions boosts cascaded SRS generation to allow the appearance of higher Raman signals of Rhodamine 6G dye solution at a low scatterer concentration of 5 mg/ml. The threshold for the formation of the first Raman signal is measured at about 60 mJ/pulse. Also, the evolution of Raman signals under several fixed pump pulses is examined to...

Erratum: “Electron residual energy due to stochastic heating in field-ionized plasma” [Phys. Plasmas 22, 113115 (2015)]

Physics of Plasmas, 2017

Relativistic self-focusing of intense laser beam in thermal collisionless quantum plasma with ramped density profile

Physical Review Special Topics - Accelerators and Beams, 2015

Propagation of a Gaussian x-ray laser beam has been analyzed in collisionless thermal quantum pla... more Propagation of a Gaussian x-ray laser beam has been analyzed in collisionless thermal quantum plasma with considering a ramped density profile. In this density profile due to the increase in the plasma density, an earlier and stronger self-focusing effect is noticed where the beam width oscillates with higher frequency and less amplitude. Moreover, the effect of the density profile slope and the initial plasma density on the laser propagation has been studied. It is found that, by increasing the initial density and the ramp slope, the laser beam focuses faster with less oscillation amplitude, smaller laser spot size and more oscillations. Furthermore, a comparison is made among the laser self-focusing in thermal quantum plasma, cold quantum plasma and classical plasma. It is realized that the laser self-focusing in the quantum plasma becomes stronger in comparison with the classical regime.

The effect of quantum correction on plasma electron heating in ultraviolet laser interaction

Journal of Applied Physics, 2015

The interaction of the sub-picosecond UV laser in sub-relativistic intensities with deuterium is ... more The interaction of the sub-picosecond UV laser in sub-relativistic intensities with deuterium is investigated. At high plasma temperatures, based on the quantum correction in the collision frequency, the electron heating and the ion block generation in plasma are studied. It is found that due to the quantum correction, the electron heating increases considerably and the electron temperature uniformly reaches up to the maximum value of 4.91 Â 10 7 K. Considering the quantum correction, the electron temperature at the laser initial coupling stage is improved more than 66.55% of the amount achieved in the classical model. As a consequence, by the modified collision frequency, the ion block is accelerated quicker with higher maximum velocity in comparison with the one by the classical collision frequency. This study proves the necessity of considering a quantum mechanical correction in the collision frequency at high plasma temperatures. V

Relativistic Gaussian laser beam self-focusing in collisional quantum plasmas

Laser and Particle Beams, 2015

Propagation of Gaussian X-ray laser beam is presented in collisional quantum plasma and the beam ... more Propagation of Gaussian X-ray laser beam is presented in collisional quantum plasma and the beam width oscillation is studied along the propagation direction. It is noticed that due to energy absorption in collisional plasma, the laser energy drops to an amount less than the critical value of the self-focusing effect and consequently, the laser beam defocuses. It is found that the oscillation amplitude of the laser spot size enhances while passing through collisional plasma. For the greater values of collision frequency, the beam width oscillates with higher amplitude and defocuses in a shallower plasma depth. Also, it is realized that in a dense plasma environment, the laser self-focusing occurs earlier with the higher oscillation amplitude, smaller laser spot size and more oscillations.

Electron trapping and field propagation in laser-plasma interaction with density transition

2008 IEEE 35th International Conference on Plasma Science, 2008

This paper investigates that by using a new electron density transition in plasma, the wave break... more This paper investigates that by using a new electron density transition in plasma, the wave breaking threshold was reduced and transversely electron injection into the acceleration phase of the wake field was increased. Numerical results identify that injected electron bunch causes to modification of the wake field. By optimization of transient length and injected charge of electron, electromagnetic propagation and electron density variation in plasma has been evaluated and the efficient energy and gain of electrons have been obtained.

Enhancement of proton acceleration by frequency-chirped laser pulse in radiation pressure mechanism

Physics of Plasmas, 2015

The transition from hole-boring to light-sail regime of radiation pressure acceleration by freque... more The transition from hole-boring to light-sail regime of radiation pressure acceleration by frequency-chirped laser pulses is studied using particle-in-cell simulation. The penetration depth of laser into the plasma with ramped density profile increases when a negatively chirped laser pulse is applied. Because of this induced transparency, the laser reflection layer moves deeper into the target and the hole-boring stage would smoothly transit into the light-sail stage. An optimum chirp parameter which satisfies the laser transparency condition, a0≈πnel/ncλ, is obtained for each ramp scale length. Moreover, the efficiency of conversion of laser energy into the kinetic energy of particles is maximized at the obtained optimum condition. A relatively narrow proton energy spectrum with peak enhancement by a factor of 2 is achieved using a negatively chirped pulse compared with the un-chirped pulse.

Electron heating enhancement by frequency-chirped laser pulses

Journal of Applied Physics, 2014

ABSTRACT Propagation of a chirped laser pulse with a circular polarization through an uprising pl... more ABSTRACT Propagation of a chirped laser pulse with a circular polarization through an uprising plasma density profile is studied by using 1D-3V particle-in-cell simulation. The laser penetration depth is increased in an overdense plasma compared to an unchirped pulse. The induced transparency due to the laser frequency chirp results in an enhanced heating of hot electrons as well as increased maximum longitudinal electrostatic field at the back side of the solid target, which is very essential in target normal sheath acceleration regime of proton acceleration. For an applied chirp parameter between 0.008 and 0.01, the maximum amount of the electrostatic field is improved by a factor of 2. Furthermore, it is noticed that for a chirped laser pulse with a0 = 5, because of increasing the plasma transparency length, the laser pulse can penetrate up to about ne ≈ 6nc, where nc is plasma critical density. It shows 63% increase in the effective critical density compared to the relativistic induced transparency regime for an unchirped condition.

Effect of quantum correction on the acceleration and delayed heating of plasma blocks

Physical Review E, 2012

The interaction of laser pulses of picosecond duration and terawatt to petawatt power accelerated... more The interaction of laser pulses of picosecond duration and terawatt to petawatt power accelerated for the very fast undistorted plasma blocks for deuterium DD or deuterium tritium fast ignition is investigated. Based on the direct and instant conversion of laser energy into mechanical motion by nonlinear (ponderomotive) forces, any thermal pressure generation is delayed by the collision process. Following the studying of the classical collision frequency, it is found that the quantum modified collision at higher energies results in a correction by about 15% reduction of the delay.

Parametric study of ultra-intense laser interaction with uniform and nano-porous near-critical plasmas

AIP Advances, 2020

Paper published as part of the special topic on Chemical Physics, Energy, Fluids and Plasmas, Mat... more Paper published as part of the special topic on Chemical Physics, Energy, Fluids and Plasmas, Materials Science and Mathematical Physics ARTICLES YOU MAY BE INTERESTED IN Generation of energetic ring-shaped ion beam from relativistic Laguerre-Gaussian laser pulse interacting with micro-structure targets Physics of Plasmas 27, 053105 (2020);

Random laser of rhodamine 6G dye solution embedded with ZnO microstructures

Optics and Photonics Society of Iran, 2019

In this study, Zinc oxide microstructures with high porosity and surface area to volume ratio in ... more In this study, Zinc oxide microstructures with high porosity and surface area to volume ratio in order to the light localization has been selected and synthesized. Characterization measurements; such as SEM, XRD and EDAX has been carried out on the structures. Random laser emission with coherence feedback from rhodamine6G solution embedded ZnO microstructures and effect of the pump energy on spectrum emission variation have been investigated.

Comprehensive study of anomalous hysteresis behavior in perovskite-based solar cells

Perovskite solar cells (PSCs) have shown remarkable progress with the rapid increase in power con... more Perovskite solar cells (PSCs) have shown remarkable progress with the rapid increase in power conversion efficiency to reach 25.7% over the last few years. However, it is difficult to precisely determine the energy conversion efficiency for PSC, because of anomalous current density- voltage (J-V) hysteresis. Normal J-V hysteresis has been reported in many papers, where the backward scan (BS) performance is higher than the forward scan (FS) one. In this work, using Drift-Diffusion Modeling (DDM), normal hysteretic behavior associated with ion migration with different scanning rates, pre-bias voltages, and charge-carrier mobility is studied. In addition, the inverted J − V hysteresis by modification of the simulation model, where anions and cations flux towards the transport layers and are accumulated simultaneously on both sides, is achieved. It is also found that the flux parameter values (gae and gch) play a critical role in the reduction of inverted hysteresis and the efficiency e...

Mode-controlled random laser assisted by stimulated Raman scattering

Optics Communications, 2021

Abstract In this study, a reproducible and stable mode random laser is fabricated from Rhodamine ... more Abstract In this study, a reproducible and stable mode random laser is fabricated from Rhodamine 6G dye-containing ZnO@C-N microstructures by using an approach based on the coupling of the stimulated Raman scattering effect and random lasing process. Under intense pump energy, the Raman peaks of Rhodamine 6G work as seeds, and multiple elastic scattering in the disordered medium will amplify them. On the other hand, ZnO@C-N porous microstructures with plenty of nanosheets and high surface area effectively act as scatterer centers in providing strong multiple elastic scattering. So that, the strong feedback from nanosheets of the individual microstructures, allows the system to operate at a low concentration of scatterers (as low as 2mg/ml). Moreover, the enhancement of Raman modes as a function of the pump pulse energies and scatterers concentrations is examined. The results show that the Raman modes after manifestation are stable and reproduce well from pulse-to-pulse pump energy variation. Our findings introduce a new approach to tune the wavelength of random lasers for real applications and also enable the laser mode selection.

Target Nano-particles size effect on the laser proton acceleration in the TNSA mechanism

On Nonlinear Evolutions of the Intense, Short Laser Pulse in the Under-Dense Plasma

arXiv: Plasma Physics, 2016

Nonlinear evolutions of an ultra-intense, short laser pulse due to the wake excitation inside the... more Nonlinear evolutions of an ultra-intense, short laser pulse due to the wake excitation inside the plasma are studied by means of detailed Particle-In-Cell (PIC) simulations and comprehensive analyses. Pulse lengths both longer and shorter than the plasma wavelength are considered. It is turned out that the system shows adiabatic behavior as long as the plasma evolves very slowly in the Pulse Co-Moving (PCM) frame due to the ignorable radiation back-reactions. A sophisticated treatment of the adiabatic regime is presented, based on the proper application of the local conservation laws in the PCM frame in conjunction with the Lorentz transformations. In this context, equations for the overall pulse evolutions are reduced into a single equation in terms of the global pulse group-velocity. Due to the proven equality between the local phase velocities of the plasma wave and the radiation, anomalies are observed in this regime, in the global group velocity and the plasma dispersion. The g...

Crystal morphology effect on optical properties of halide Perovskite thin films

Optics and Photonics Society of Iran, 2019

Optical response of CH3NH3PbBr3 perovskite thin films to the variations of procures stoichiometry

Optics and Photonics Society of Iran, 2020

In addition to the successful use of organic-inorganic hybrid perovskite materials in photovoltai... more In addition to the successful use of organic-inorganic hybrid perovskite materials in photovoltaics, these materials have been shown significant role in perovskite based light emitting diodes development. In this work, the effect of the variation precursor stoichiometry of CH3NH3PbBr3 perovskite on structure, morphology and optical response of thin films by using of ،XRD ،UV-Vis ،PL and TRPL characteristic techniques has been studied. The results revealed that, the crystallinity and morphology of perovskite thin films for precursor’s ratio of 1/25:1 compare to the case of 1:1 is improved and the radiative recombination rate of the carrier and photoluminescence intensity is increased.

Theory of the ultra-intense short-pulse laser interaction with under-dense plasma

A comprehensive theory is proposed to describe the propagation and absorption of ultra-intense, s... more A comprehensive theory is proposed to describe the propagation and absorption of ultra-intense, short laser pulse through the under-dense plasma. The kinetic aspects of plasma are fully incorporated using extensive particle-in-cell (PIC) simulations. It is turned out that the plasma behavior is characterized by both its density and the ratio of the pulse length to the plasma wavelength. According to exact analyses and direct simulation evidences, at ultra-low densities the laser pulse is adiabatically depleted (absorbed) by the wake excitation. And the depletion is accompanied by the overall radiation red-shift. At these densities, for pulse lengths larger than the plasma wavelength the Raman type scatterings also occur without causing instability. When the plasma density grows toward the critical density, a completely new regime appears with the main character of highly unsteady light propagation. Here, based on analyses and simulations, the radiation pressure induced wave breaking...

The effect of solvent on random laser of Rhodamine 6G dye solution with ZnO@C-N microstructures

Optics and Photonics Society of Iran, 2020

In this study, Carbon and Nitrogen doped Zinc oxide microstrcturess as scatterer centers in Rhoda... more In this study, Carbon and Nitrogen doped Zinc oxide microstrcturess as scatterer centers in Rhodamine 6G dye as gain media has been selected and synthesized. The existence of the sheetlike structures in ZnO@C-N sample due to the Carbon and Nitrogen dopants, is improves the scatterers morphologies .Later on, the random laser emission for two independent samples for the same concentration of gain media and scatterer centers, with different solvents in order to evaluating the effect of the solvent on output spectrum, have been studied. The results show higher polarity of solvent leads increasing the red shift and decreasing the spectrum intensity and does not have any significant effect on localization threshold and output modes.

Short Intense Laser Pulse Depletion and Scattering in Under-Dense Plasma

Nonlinear evolutions of an ultra-intense, short laser pulse due to the wake excitation inside the... more Nonlinear evolutions of an ultra-intense, short laser pulse due to the wake excitation inside the plasma are studied by means of detailed particle-in-cell simulations and comprehensive analyses. Pulse lengths both longer and shorter than the plasma wavelength are considered. A new adiabatic regime of the interaction is identified in connection with the quasi-static being of the plasma in the pulse commoving frame. This situation occurs when radiation back-reactions are ignorable in the commoving frame against the measured high plasma momentum. By formulating this regime in terms of the local conservation laws, we calculate the overall pulse depletion and more importantly the global pulse group velocity. The outcome for the group velocity shows non-explicit density dependency and, strangely, remains above the linear value over a long time period. Further, we examine the model adequacy at different applied parameters via comparison with simulations. It is turned out that for pulse len...

Narrow-band random Raman lasing from Rhodamine 6G assisted by cascaded stimulated Raman scattering effect

Scientific Reports, 2021

This study reports the first experimental observation of cascaded stimulated Raman scattering (SR... more This study reports the first experimental observation of cascaded stimulated Raman scattering (SRS) generation in a colloidal disordered medium. Generation of the cascaded effect requires both a high Raman gain and pump power in the disordered medium. Here, to extend effective path lengths of photons into the Raman gain medium for producing additional SRS processes, ZnO microspheres with abundant nano-protrusions as suitable scattering centers are proposed. It is explained that nano-protrusions on the surface of the spheres can act as nano reflectors and significantly provide potent feedback in the disordered system. This provided feedback via nano-protrusions boosts cascaded SRS generation to allow the appearance of higher Raman signals of Rhodamine 6G dye solution at a low scatterer concentration of 5 mg/ml. The threshold for the formation of the first Raman signal is measured at about 60 mJ/pulse. Also, the evolution of Raman signals under several fixed pump pulses is examined to...

Erratum: “Electron residual energy due to stochastic heating in field-ionized plasma” [Phys. Plasmas 22, 113115 (2015)]

Physics of Plasmas, 2017

Relativistic self-focusing of intense laser beam in thermal collisionless quantum plasma with ramped density profile

Physical Review Special Topics - Accelerators and Beams, 2015

Propagation of a Gaussian x-ray laser beam has been analyzed in collisionless thermal quantum pla... more Propagation of a Gaussian x-ray laser beam has been analyzed in collisionless thermal quantum plasma with considering a ramped density profile. In this density profile due to the increase in the plasma density, an earlier and stronger self-focusing effect is noticed where the beam width oscillates with higher frequency and less amplitude. Moreover, the effect of the density profile slope and the initial plasma density on the laser propagation has been studied. It is found that, by increasing the initial density and the ramp slope, the laser beam focuses faster with less oscillation amplitude, smaller laser spot size and more oscillations. Furthermore, a comparison is made among the laser self-focusing in thermal quantum plasma, cold quantum plasma and classical plasma. It is realized that the laser self-focusing in the quantum plasma becomes stronger in comparison with the classical regime.

The effect of quantum correction on plasma electron heating in ultraviolet laser interaction

Journal of Applied Physics, 2015

The interaction of the sub-picosecond UV laser in sub-relativistic intensities with deuterium is ... more The interaction of the sub-picosecond UV laser in sub-relativistic intensities with deuterium is investigated. At high plasma temperatures, based on the quantum correction in the collision frequency, the electron heating and the ion block generation in plasma are studied. It is found that due to the quantum correction, the electron heating increases considerably and the electron temperature uniformly reaches up to the maximum value of 4.91 Â 10 7 K. Considering the quantum correction, the electron temperature at the laser initial coupling stage is improved more than 66.55% of the amount achieved in the classical model. As a consequence, by the modified collision frequency, the ion block is accelerated quicker with higher maximum velocity in comparison with the one by the classical collision frequency. This study proves the necessity of considering a quantum mechanical correction in the collision frequency at high plasma temperatures. V

Relativistic Gaussian laser beam self-focusing in collisional quantum plasmas

Laser and Particle Beams, 2015

Propagation of Gaussian X-ray laser beam is presented in collisional quantum plasma and the beam ... more Propagation of Gaussian X-ray laser beam is presented in collisional quantum plasma and the beam width oscillation is studied along the propagation direction. It is noticed that due to energy absorption in collisional plasma, the laser energy drops to an amount less than the critical value of the self-focusing effect and consequently, the laser beam defocuses. It is found that the oscillation amplitude of the laser spot size enhances while passing through collisional plasma. For the greater values of collision frequency, the beam width oscillates with higher amplitude and defocuses in a shallower plasma depth. Also, it is realized that in a dense plasma environment, the laser self-focusing occurs earlier with the higher oscillation amplitude, smaller laser spot size and more oscillations.

Electron trapping and field propagation in laser-plasma interaction with density transition

2008 IEEE 35th International Conference on Plasma Science, 2008

This paper investigates that by using a new electron density transition in plasma, the wave break... more This paper investigates that by using a new electron density transition in plasma, the wave breaking threshold was reduced and transversely electron injection into the acceleration phase of the wake field was increased. Numerical results identify that injected electron bunch causes to modification of the wake field. By optimization of transient length and injected charge of electron, electromagnetic propagation and electron density variation in plasma has been evaluated and the efficient energy and gain of electrons have been obtained.

Enhancement of proton acceleration by frequency-chirped laser pulse in radiation pressure mechanism

Physics of Plasmas, 2015

The transition from hole-boring to light-sail regime of radiation pressure acceleration by freque... more The transition from hole-boring to light-sail regime of radiation pressure acceleration by frequency-chirped laser pulses is studied using particle-in-cell simulation. The penetration depth of laser into the plasma with ramped density profile increases when a negatively chirped laser pulse is applied. Because of this induced transparency, the laser reflection layer moves deeper into the target and the hole-boring stage would smoothly transit into the light-sail stage. An optimum chirp parameter which satisfies the laser transparency condition, a0≈πnel/ncλ, is obtained for each ramp scale length. Moreover, the efficiency of conversion of laser energy into the kinetic energy of particles is maximized at the obtained optimum condition. A relatively narrow proton energy spectrum with peak enhancement by a factor of 2 is achieved using a negatively chirped pulse compared with the un-chirped pulse.

Electron heating enhancement by frequency-chirped laser pulses

Journal of Applied Physics, 2014

ABSTRACT Propagation of a chirped laser pulse with a circular polarization through an uprising pl... more ABSTRACT Propagation of a chirped laser pulse with a circular polarization through an uprising plasma density profile is studied by using 1D-3V particle-in-cell simulation. The laser penetration depth is increased in an overdense plasma compared to an unchirped pulse. The induced transparency due to the laser frequency chirp results in an enhanced heating of hot electrons as well as increased maximum longitudinal electrostatic field at the back side of the solid target, which is very essential in target normal sheath acceleration regime of proton acceleration. For an applied chirp parameter between 0.008 and 0.01, the maximum amount of the electrostatic field is improved by a factor of 2. Furthermore, it is noticed that for a chirped laser pulse with a0 = 5, because of increasing the plasma transparency length, the laser pulse can penetrate up to about ne ≈ 6nc, where nc is plasma critical density. It shows 63% increase in the effective critical density compared to the relativistic induced transparency regime for an unchirped condition.

Effect of quantum correction on the acceleration and delayed heating of plasma blocks

Physical Review E, 2012

The interaction of laser pulses of picosecond duration and terawatt to petawatt power accelerated... more The interaction of laser pulses of picosecond duration and terawatt to petawatt power accelerated for the very fast undistorted plasma blocks for deuterium DD or deuterium tritium fast ignition is investigated. Based on the direct and instant conversion of laser energy into mechanical motion by nonlinear (ponderomotive) forces, any thermal pressure generation is delayed by the collision process. Following the studying of the classical collision frequency, it is found that the quantum modified collision at higher energies results in a correction by about 15% reduction of the delay.