Yousef I Salamin

Yousef I Salamin
American University of Sharjah | AUS

PhD

About

104
Publications
13,206
Reads
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2,566
Citations
Citations since 2016
21 Research Items
889 Citations
2016201720182019202020212022020406080100120140
2016201720182019202020212022020406080100120140
2016201720182019202020212022020406080100120140
2016201720182019202020212022020406080100120140
Introduction
Laser acceleration. Ultra-high energy cosmic rays.
Skills and Expertise
Additional affiliations
September 2003 - present
American University of Sharjah
Position
  • Professor
September 2003 - November 2015
American University of Sharjah
Position
  • Professor
January 1988 - August 2003
Birzeit University
Position
  • Professor

Publications

Publications (104)
Article
Full-text available
High-energy spin-polarized electron, positron, and \(\gamma\)-photon beams have many significant applications in the study of material properties, nuclear structure, particle physics, and high-energy astrophysics. Thus, efficient production of such polarized beams attracts a broad spectrum of research interests. This is driven mainly by the rapid a...
Preprint
Full-text available
High-energy spin-polarized electron, positron, and γ-photon beams have many significant applications in the study of material properties, nuclear structure, particle physics, and high-energy astrophysics. Thus, efficient production of such polarized beams attracts a broad spectrum of research interests. This is driven mainly by the rapid advancemen...
Preprint
Full-text available
An all-optical method of ultrafast spin rotation is put forward to precisely manipulate the polarization of relativistic charged particle beams of leptons or ions. In particular, laser-driven dense ultrashort beams are manipulated via single-shot interaction with a co-propagating moderate temporally asymmetric (frequency-chirped or subcycle THz) la...
Preprint
Full-text available
Employing a two-parameter model for representing the radiation field, the theory of cosmic-ray acceleration by cyclotron autoresonance is analytically generalized here to include any state of polarization. The equations are derived rigorously and used to investigate the dynamics of the nuclides $_1$H$^1$, $_2$He$^4$, $_{26}$Fe$^{56}$, and $_{28}$Ni...
Article
Full-text available
A two-parameter model for chirping the frequency of a plane-wave laser pulse is introduced using a binomial expansion. Acceleration of single electrons, through interaction with the plane-wave binomially chirped laser pulse, is investigated by solving the relativistic equations of motion, analytically and numerically. Multi-GeV energy gains are rep...
Article
Full-text available
A Zevatron is an accelerator scheme envisaged to accelerate particles to ZeV energies (1 ZeV = 10 ²¹ eV). Schemes, most notably the internal shock model, have been proposed to explain the acceleration of ultra-high-energy cosmic-ray particles that have been sporadically detected reaching Earth since 1962. Here, the cyclotron auto-resonance accelera...
Preprint
Full-text available
A Zevatron is an accelerator scheme envisaged to accelerate particles to ZeV energies (1 ZeV = $10^{21}$ eV). Schemes, most notably the internal shock model, have been proposed to explain the acceleration of ultra-high-energy cosmic-ray (UHECR) particles that have been sporadically detected reaching Earth since 1962. Here, the cyclotron auto-resona...
Article
Full-text available
In laser-solid interactions, electrons may be generated and subsequently accelerated to energies of the order of magnitude of the ponderomotive limit, with the underlying process dominated by direct laser acceleration. The breaking of this limit, realized here by a radially polarized laser pulse incident upon a wire target, can be associated with s...
Article
Full-text available
Generation of high-flux vortex γ -ray pulses is investigated in the interaction of ultraintense Bessel–Bessel laser bullets colliding head-on with ultrarelativistic electron bunches in the quantum radiation-dominated regime. In the simulations, a semiclassical Monte–Carlo method is used, based on the radiation probabilities in the local constant fi...
Article
Full-text available
A Bessel-Bessel laser bullet is the ultra-short and tightly-focused analogue of a non-diffracting and non-dispersing laser Bessel beam. Analytic investigation of the energy, linear momentum, energy flux, and angular momentum, associated with the fields of a Bessel-Bessel bullet, propagating in an under-dense plasma, is conducted in this work. The a...
Article
Full-text available
Three of the headings of Table 1, which have been switched by mistake in our paper, are corrected here. The rest of the paper, including all results and conclusions, remain intact.
Preprint
Full-text available
In laser-solid interactions, electrons may be generated and subsequently accelerated to energies of the order-of-magnitude of the ponderomotive limit, with the underlying process dominated by direct laser acceleration. Breaking this limit, realized here by a radially-polarized laser pulse incident upon a wire target, can be associated with several...
Article
Full-text available
A simple model is introduced for the fields of a chirped laser pulse. As an application, dynamics of laser-acceleration of a single electron by the fields of a pulse, with a sin4 envelope, is investigated. Multi-GeV energy gains from interaction with pulses of peak intensity I0~1020 W/cm2, are reported.
Article
Full-text available
Encouraged by recent advances in radially-polarized laser technology, simulations have been performed of electron acceleration by a tightly-focused, ultra-short pulse in a parabolic plasma micro-channel. Milli-joule laser pulses, generated at kHz repetition rates, are shown to produce electron bunches of MeV energy, pC charge, low emittance and low...
Conference Paper
Full-text available
Fields of a laser Bessel-Bessel bullet are presented, from solution to the wave equations of the scalar and vector potentials in the presence of an under-dense plasma. Propagation over many centimeters without distortion is demonstrated. © 2019 The Author(s)
Article
Full-text available
Considerable theoretical and experimental work has lately been focused on waves localized in time and space. In optics, waves of that nature are often referred to as light bullets. The most fascinating feature of light bullets is their propagation without appreciable distortion by diffraction or dispersion. Here, analytic expressions for the fields...
Article
Full-text available
Provided the intensity is not too high (for example, with I << 1018 W/cm2, for a wavelength of 1 μm), response of an under-dense plasma to the fields of a laser pulse can still be considered linear, and inhomogeneous wave equations for the vector and scalar potentials A and Φ, respectively, may be derived from Maxwell’s equations. A rigorous, but a...
Article
Full-text available
Analytic expressions for the fields of a radially polarized, ultrashort and tightly focused laser pulse propagating in a linear-response plasma are derived and discussed. The fields are obtained from solving the inhomogenous wave equations for the vector and scalar potentials, linked by the Lorenz gauge, in a plasma background. First the scalar pot...
Article
Full-text available
Fully analytic expressions, for the electric and magnetic fields of an ultrashort and tightly focused laser pulse of the radially polarized category, are presented to lowest order of approximation. The fields are derived from scalar and vector potentials, along the lines of our earlier work for a similar pulse of the linearly polarized variety. A s...
Article
Full-text available
Preface: The International Conference Frontiers in Theoretical and Applied Physics |UAE 2017 was organized by the Department of Physics at the American University of Sharjah (AUS) in partnership with the Emirates Mars Mission and Mohammed Bin Rashid Space Center (MBRSC) in Dubai-United Arab Emirates. The conference was endorsed by the American Phys...
Data
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Article
Full-text available
Analytic expressions for the electric and magnetic fields of an ultrashort, tightly focused, linearly polarized laser pulse are derived, to lowest order of a truncated power-series expansion, from vector and scalar potentials. Clear steps are described for the analytic and numerical evaluation of higher-order terms in the series, to any desired acc...
Article
Full-text available
Analytic expressions for the electric and magnetic fields of a radially polarized ultrashort and tightly focused laser pulse, propagating in vacuum, are derived from scalar and vector potentials satisfying simple initial conditions. It is shown that for a pulse of axial length comparable to a wavelength, only the zeroth (lowest-order) term in a pow...
Article
Full-text available
Analytic expressions for the electromagnetic fields of an ultrashort, tightly focused, laser pulse in vacuum are derived from scalar and vector potentials, using on equal footing two small parameters connected with the waist size of the laser beam and its duration. Compared with fields derived from a complex-source-point approach and a Lax series e...
Article
Full-text available
A vacuum autoresonance accelerator scheme for electrons, which employs terahertz radiation and currently available magnetic fields, is suggested. Based on numerical simulations, parameter values, which could make the scheme experimentally feasible, are identified and discussed.
Article
Full-text available
Several aspects of the interaction of particle beams with ultrastrong laser fields are discussed. Firstly, we consider regimes when radiation reaction is not essential and it is demonstrated that employing chirped laser pulses, significant improvement of the direct acceleration of particles can be achieved. Results from single- and many-particle ca...
Article
Full-text available
Theoretical investigations are presented, and their results are discussed, of the laser acceleration of a single electron by a chirped pulse. Fields of the pulse are modeled by simple plane-wave oscillations and a $\cos^2$ envelope. The dynamics emerge from analytic and numerical solutions to the relativistic Lorentz-Newton equations of motion of t...
Article
Full-text available
Single MeV electrons subjected in vacuum to single high-intensity quadratically-chirped laser pulses are shown to gain multi-GeV energies. The laser pulses are modeled by finite-duration trapezoidal and $\cos^2$ pulse-shapes and the equations of motion are solved numerically. It is found that, typically, the maximum energy gain from interaction wit...
Article
Full-text available
Autoresonance laser acceleration of electrons is theoretically investigated using circularly polarized focused Gaussian pulses. Many-particle simulations demonstrate feasibility of creating over 10-GeV electron bunches of ultra-high quality (relative energy spread of order 10^-4), suitable for fundamental high-energy particle physics research. The...
Article
According to the Lawson-Woodward theorem, an electron cannot gain any energy from interaction with an ideal plane-wave laser pulse. We demonstrate analytically and numerically that chirping the frequency of the pulse distorts it in a sensitive way and leads to net energy gain by an electron submitted to it.
Article
Results from theoretical investigations are presented which show that protons can be accelerated from rest to a few hundred MeV by a 1-PW chirped radially polarized laser pulse of several hundred femtosecond duration and focused to a waist radius comparable to the radiation wavelength. Single-particle calculations are supported by many-particle and...
Article
Detailed single- and many-particle calculations are carried out for the acceleration of protons employing linearly-polarized plane-wave and tightly-focused chirped laser pulses of several ten to several hundred femtosecond durations, petawatt peak powers and relativistic peak intensities of the order of 10^21-10^22 W/cm^2 [1,2]. Analytic and numeri...
Article
The dynamics of ion acceleration in tightly focused laser beams is investigated in relativistic simulations. Studies are performed to find the optimal parameters which maximize the energy gain, beam quality, and flux. The exit ionic kinetic energy and its uncertainty are improved and the number of accelerated particles is increased by orders of mag...
Article
Full-text available
Interaction of a frequency-chirped laser pulse with single protons and a hydrogen gas target is studied analytically and by means of particle-in-cell simulations, respectively. The feasibility of generating ultraintense (10(7) particles per bunch) and phase-space collimated beams of protons (energy spread of about 1%) is demonstrated. Phase synchro...
Article
Full-text available
Calculations show that 10 keV helium and carbon ions, injected midway between two identical 1 TW-power crossed laser beams of radial polarization, can be accelerated in vacuum to energies of utility in ion lithography. As examples, identical laser beams, crossed at 10° and focused to waist radii of 7.42mum, accelerate He2+ and C6+ ions to average k...
Article
Two interfering ultra-high intensity laser beams of radial polarization are shown to accelerate protons, in vacuum, to several GeV. Both co-propagating and counter-propagating beams of slightly different frequencies and amplitudes are considered. The accelerated protons have energy gradients of several hundred GeV/m, less than 1% energy spread and...
Article
Two constants of the motion, which simplify the relativistic particle dynamics in a laser beam of radial polarization, are identified. Many-particle simulations based on the reduced set of equations of motion in a beam of relativistic intensity, demonstrate acceleration in vacuum to GeV energies of electrons, alpha particles and oxygen bare nuclei....
Article
Electrons and {alpha} particles injected midway between two ultrahigh intensity crossed laser beams of radial polarization are shown to be accelerated in vacuum to several gigaelectron volts and to have average energy gradients in excess of 150 GeV/m. A unique model of the crossing beams is suggested, which maximizes the particle energy gain and mi...
Article
Fields of a linearly polarized fundamental Gaussian beam are derived exactly using the propagation characteristics of a complex-source-point spherical wave diverging from the origin. Intensity distributions are calculated and compared with their counterparts in a truncated series. It is found that utility of the exact fields is limited by a discont...
Article
Full-text available
In this paper, the fields of a radially polarized fundamental Gaussian beam are derived with a complex-source-point spherical wave approach and then compared and contrasted with those derived recently from a Lax series to the order of ε15, where ε is the diffraction angle. It is shown that the domain of validity of the derived fields is restricted...
Article
We investigate the relativistic dynamics of electrons in intense laser fields. Examples of both free and bound electron dynamics are discussed using the approach appropriate for each particular case, i.e., either classical relativistic mechanics or relativistic quantum mechanics. The algorithm for numerically solving the Dirac equation is explained...
Article
An error, involving the last three terms in the truncated series giving the output power of a radially polarized laser system, has been detected and is corrected here.
Article
Full-text available
An error involving the coefficients of the last three terms in the truncated series giving the output power of a radially polarized laser system has been detected and is corrected here.
Article
Full-text available
Theoretical investigations show that linearly and radially polarized multiterawatt and petawatt laser beams, focused to subwavelength waist radii, can directly accelerate protons and carbon nuclei, over micron-size distances, to the energies required for hadron cancer therapy. Ions accelerated by radially polarized lasers have generally a more favo...
Article
Fields of a radially polarized petawatt laser beam, represented by a truncated series in the diffraction angle epsilon to order epsilon15 and focused to subwavelength waist radius, are shown to accelerate protons and bare nuclei to several hundred MeV per nucleon over a distance equivalent to a few laser wavelengths.
Article
Fields of a radially polarized laser beam developed recently [Y. I. Salamin, Opt. Lett.31, 2619 (2006)] are employed to show that electrons produced by atomic ionization near the focus may be accelerated to GeV energies. Conditions for producing a mono-energetic and well-collimated electron beam are discussed.
Article
Full-text available
Analytic expressions for the fields of a tightly focused Gaussian laser beam are derived, accurate to ε11, where ε is the diffraction angle. It is found that, for example, using the derived fields, the calculated power can be about 25% more accurate than when calculated using the paraxial approximation for a beam focused down to a waist radius w0∼0...
Article
Analytic expressions for the fields of a tightly focused radially polarized Gaussian laser beam are derived, accurate to epsilon5, where epsilon is the associated diffraction angle. The fields satisfy Maxwell's equations, and the calculated beam power based on them is significantly different from that of the paraxial-approximation fields.
Article
Full-text available
Explicit truncated series expressions modelling the fields of a focused radially polarized Gaussian laser beam are derived, accurate to order ε15, where ε is the associated fundamental Gaussian beam diffraction angle. The new terms make significant corrections to the known paraxial field components, the corrected fields satisfy Maxwell's equations...
Article
We present a simple analytic expression for the generalized diagonal matrix element for arbitrary β and fixed l, using the fully relativistic hydrogen wavefunctions. On the basis of this expression, exact matrix elements corresponding to the value of l in the range n - 5 ≤ l ≤ n - 1 are obtained and shown to reduce to their nonrelativistic counterp...
Article
We employ the lowest-order radially polarized axicon fields of a Gaussian laser beam to demonstrate that electrons may be accelerated from rest in vacuum to a few GeV. Petawatt power laser beams focused onto micron-size focal spots result in multi-TeV/m electron energy gradients.
Article
Full-text available
Recent advances in laser technology have pushed the frontier of maximum intensity achieved to about 1022W/cm2 and investigators currently believe even higher intensities may be reached in the near future. This, combined with other breakthroughs on the fronts of short pulse generation and high repetition rates, have stimulated considerable progress,...
Article
The dynamics of electrons injected sideways into the focal region of a tightly-focused laser beam of present-day intensity is studied by numerically solving the relativistic energy–momentum transfer equations. Correlations such as and θ–ζ are investigated, where is the ejection energy, ζ is the injection angle, and θ is the ejection angle (both mea...
Article
The fields of two linearly-polarized, co-propagated laser beams differing slightly in frequency are modelled by those of a tightly focused Gaussian beam. When a single electron is injected sideways into or near the common focus of the two beams, it gets captured and violently accelerated, reaching a maximum energy gain in excess of 2 GeV from beams...
Article
Quantum signatures of a free electron in interaction with a continuous-wave radiation field are investigated by looking for negativities in the Wigner function of the system. The free-electron wave function in the radiation field is calculated fully analytically by solving the appropriate Schrödinger equation in the Krammers-Henneberger frame. It i...
Article
Results from numerical calculations of the energy gain, by a single electron injected sideways into the focal point of a tightly focused laser beat wave, are presented and discussed. Maximum gain, of a few GeV is demonstrated, from the beat structure of two beams of present-day intensity. All results are obtained from solving the relativistic equat...
Conference Paper
Full-text available
We investigate optimum conditions for achieving maximum energy gain when electrons are scattered by tightly focused laser beams. A single-beam configuration and one that employs two beams crossing at an angle are discussed. Solution of the equations of motion is carried out numerically in each case, and the fields are modeled by those of a Gaussian...
Article
Electron motion and harmonic generation are investigated in the crossed-beam laser-accelerator scheme in a vacuum. Exact solutions of the equations of motion of the electron in plane-wave fields are given, subject to a restricted set of initial conditions. The trajectory solutions corresponding to axial injection are used to calculate precise emiss...
Article
Full-text available
An electron injected sideways into the focal region of a tightly-focused laser beam encounters strong field variations in both space and time. Thus, momentum may be imparted to it by the field in the nature of a small number of violent impulses. Results from single-particle calculations are presented which demonstrate electron acceleration to GeV e...
Article
Full-text available
By numerically solving the relativistic equations of motion of a single electron in laser fields modeled by those of a Gaussian beam, we demonstrate electron capture by, reflection from, and transmission through the beam. In modeling the fields, terms of order up to ϵ5, where ϵ is the diffraction angle, are retained. All cases of capture are accomp...
Article
Full-text available
By numerically solving the relativistic equations of motion of a single electron in laser fields modeled by those of a Gaussian beam, we demonstrate electron capture by, reflection from, and transmission through the beam. In modeling the fields, terms of order up to ɛ5, where ɛ is the diffraction angle, are retained. All cases of capture are accomp...
Article
Full-text available
State-of-the-art petawatt laser beams may be focused down to few-micron spot sizes and can produce violent electron acceleration as a result of the extremely intense and asymmetric fields. Classical fifth-order calculations in the diffraction angle show that electrons, injected sideways into the tightly focused laser beam, get captured and gain ene...
Article
The relativistic dynamics of single particles and thin crystals is investigated in very short, intense laser pulses. Single particle acceleration from 100 MeV to GeV energies is shown for electrons in Gaussian beams of few micron widths and crossed laser beams of 0.1 radians crossing angles. High harmonic generation in the X-ray regime is predicted...
Article
We solve exactly analytically the relativistic equation of motion of a single electron injected initially at an angle to the direction of propagation of a circularly-polarized plane-wave laser field, of arbitrary intensity, and a uniform electric field. It is shown, in principle, that the electron may be accelerated to high energies in this environ...
Article
Full-text available
An exact analytical solution for the equation of motion of a single relativistic electron, injected initially at some angle ξ to the propagation direction of a linearly polarized plane-wave laser field of arbitrary intensity and a uniform electric field oriented anti-parallel to the laser propagation direction, is developed. The solution is then us...
Chapter
In general, theoretical analysis of the interaction of a single electron with the radiation field, in vacuum, may be carried out at various levels of sophistication, with the transition from one level to the next made on clear physical grounds. Under conditions to be described below, a nonrelativistic classical description is adequate. However, in...
Article
Full-text available
We present an exact analytic investigation of the electron dynamics in the field of two linearly polarized interfering copropagating laser beams of different frequencies, arbitrary intensities, and arbitrary relative polarizations. In one part of the paper, the laser fields are modelled by plane waves and in another part the fields are allowed to h...
Article
Full-text available
We study the relativistic dynamics of a single electron in a plane-wave laser field and a static magnetic field oriented along the laser propagation direction. A set of exact solutions, that demonstrate acceleration to TeV energies in vacuum by the mechanism of resonance between the electron cyclotron frequency and the Doppler-shifted laser frequen...
Article
Full-text available
We present an exact plane-wave-based analysis of the vacuum acceleration, to energy gradients in the TeV/m range, of a single electron, using two laser beams crossing at an arbitrary angle. Our analysis of the dynamics evolves from analytic solutions to the relativistic equations of motion and predicts that, for a given laser intensity, a unique cr...
Article
Full-text available
An exact manifestly covariant solution to the equation of motion of a single electron in the fields of two plane waves of arbitrary intensities, frequencies, and polarizations is presented and used to derive the main working equations of the vacuum beat wave accelerator.
Article
Full-text available
We point out that, the way it is reported, the solution to the equation of motion of a relativistic electron in the field of two electromagnetic waves advanced recently by Amatuni and Pogorelsky [Phys. Rev. ST Accel. Beams 1, 034001 (1998)] does not handle the case of two copropagating waves differing in frequency. An equivalent form for that solut...
Article
Full-text available
Exact expressions for the electron trajectory and energy are discussed, which predict very high acceleration, in vacuum, by a laser field and a uniform magnetic field. The laser field is modeled by a sin2 pulse and the initial electron motion, propagation of the laser pulse, and the magnetic field are all chosen in the same direction. An accelerati...
Article
When a fast free electron is subjected to a high intensity plane-wave laser field propagating in the same direction as that of its initial motion, none of the harmonics of order higher than n=1 are scattered in the forward and backward directions if the field is circularly polarized. Moreover, backscattering of harmonics of odd integer order only o...