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دسترسی آزاد مقاله
1 - Quasi monoenergetic electron bunch generation by frequency variation laser pulse in magnetized plasma
Azadeh AhmadianAbstractThe effect of the frequency variation of laser pulse in uniform magnetized plasma is considered in one-dimensional laser wakefield acceleration and carried out particle simulation. It is shown that wakefield amplitude is increased threefold for the negative Gaus چکیده کاملAbstractThe effect of the frequency variation of laser pulse in uniform magnetized plasma is considered in one-dimensional laser wakefield acceleration and carried out particle simulation. It is shown that wakefield amplitude is increased threefold for the negative Gaussian chirped laser pulse in the magnetized plasma. In our simulation, electrons with initial energy about 0.3 MeV with initial energy spread about 10 % were trapped, effectively compressed in longitudinal direction and accelerated to ultra-relativistic energy about 1.3 GeV with final energy spread about 6 %. پرونده مقاله -
دسترسی آزاد مقاله
2 - Effect of obliqueness of external magnetic field on the characteristics of magnetized plasma wakefield
Maryam Manouchehrizadeh Davoud DorranianAbstractA direct three-dimensional model to study the wakefield in underdense magnetized plasma is introduced. The model is based on an analytic procedure by Laplace transformation for calculating the magnetized plasma wake equations. Wakefield is excited using a high-i چکیده کاملAbstractA direct three-dimensional model to study the wakefield in underdense magnetized plasma is introduced. The model is based on an analytic procedure by Laplace transformation for calculating the magnetized plasma wake equations. Wakefield is excited using a high-intensity ultrashort laser beam. In the presence of external magnetic field perpendicular to the direction of the laser pulse propagation direction, plasma electrons rotate around the magnetic field lines, leading to the generation of an electromagnetic component of the plasma wakes at plasma frequency. This component is polarized perpendicularly to the direct current magnetic field lines and propagates in the forward direction and normal direction with respect to the laser pulse propagation direction, both perpendiculars to the direction of the applied magnetic field. Intensity of the radiation in different plasma densities and different magnetic field strengths has been observed. پرونده مقاله -
دسترسی آزاد مقاله
3 - Soliton reflection in a magnetized inhomogeneous warm plasma: effect of ionization
Hitendra K. Malik Jyoti Ravinder KumarAbstractThe reflection of nonlinear solitary waves is studied in a plasma under the effect of an external magnetic field and constant ionization along with finite ion temperature. To investigate the reflection of solitary waves, relevant modified Korteweg–deVries equati چکیده کاملAbstractThe reflection of nonlinear solitary waves is studied in a plasma under the effect of an external magnetic field and constant ionization along with finite ion temperature. To investigate the reflection of solitary waves, relevant modified Korteweg–deVries equations for the right and left going waves are derived, and coupled at the point of reflection for obtaining the expression of reflection coefficient. The solitary waves are found to shift after their reflection. Variation of reflection coefficient and shift are studied for different plasma parameters like ion temperature, ionization rate and wave propagation angle or the obliqueness of magnetic field. پرونده مقاله -
دسترسی آزاد مقاله
4 - Surface wave excitations on magnetized over-dense plasma
Sedigheh Miraboutalebi L Rajaee L Farhang MatinAbstractThe dominant procedure for the transmission of electromagnetic waves on an over-dense plasma layer is the excitation of surface waves. The conditions for this wave excitation on the surface of over-dense plasma, hence, become important. Here, the dispersion rela چکیده کاملAbstractThe dominant procedure for the transmission of electromagnetic waves on an over-dense plasma layer is the excitation of surface waves. The conditions for this wave excitation on the surface of over-dense plasma, hence, become important. Here, the dispersion relation for the surface wave excitation on an over-dense plasma medium which is exposed to a magnetic field is studied. These investigations lead to the condition required for producing the surface waves. By this dispersion condition, an analytical function for the wave vector in terms of the phase velocity and the cyclotron and collision frequencies is established. Specifically, the outgoings of these dependencies and also the condition for exciting more stable waves are discussed. پرونده مقاله -
دسترسی آزاد مقاله
5 - The effect of external magnetic field on the density distributions and electromagnetic fields in the interaction of high-intensity short laser pulse with collisionless underdense plasma
Masoomeh Mahmoodi-Darian Mehdi Ettehadi-Abari Mahsa SedaghatAbstractLaser absorption in the interaction between ultra-intense femtosecond laser and solid density plasma is studied theoretically here in the intensity range Iλ2≃1014-1016Wcm-2μm2documentclass[12pt]{minimal} usepackage{amsmath} usepackage{wasysym} usepackage{amsfont چکیده کاملAbstractLaser absorption in the interaction between ultra-intense femtosecond laser and solid density plasma is studied theoretically here in the intensity range Iλ2≃1014-1016Wcm-2μm2documentclass[12pt]{minimal} usepackage{amsmath} usepackage{wasysym} usepackage{amsfonts} usepackage{amssymb} usepackage{amsbsy} usepackage{mathrsfs} usepackage{upgreek} setlength{oddsidemargin}{-69pt} egin{document}$$ I{lambda^2} simeq 10^{14}{-}10^{16};{ ext{W}};{{ ext{cm}}^{-2}} ;upmu{{ ext{m}}^{2}} $$end{document}. The collisionless effect is found to be significant when the incident laser intensity is less than 1016Wcm-2μm2documentclass[12pt]{minimal} usepackage{amsmath} usepackage{wasysym} usepackage{amsfonts} usepackage{amssymb} usepackage{amsbsy} usepackage{mathrsfs} usepackage{upgreek} setlength{oddsidemargin}{-69pt} egin{document}$$ 10^{16};{ ext{W}};{{ ext{cm}}^{-2}};upmu{{ ext{m}}^{2}} $$end{document}. In the current work, the propagation of a high-frequency electromagnetic wave, for underdense collisionless plasma in the presence of an external magnetic field is investigated. When a constant magnetic field parallel to the laser pulse propagation direction is applied, the electrons rotate along the magnetic field lines and generate the electromagnetic part in the wake with a nonzero group velocity. Here, by considering the ponderomotive force in attendance of the external magnetic field and assuming the isothermal collisionless plasma, the nonlinear permittivity of the plasma medium is obtained and the equation of electromagnetic wave propagation in plasma is solved. Here, by considering the effect of the ponderomotive force in isothermal collisionless magnetized plasma, it is shown that by increasing the laser pulse intensity, the electrons density profile leads to steepening and the electron bunches of plasma become narrower. Moreover, it is found that the wavelength of electric and magnetic field oscillations increases by increasing the external magnetic field and the density distribution of electrons also grows in comparison to the unmagnetized collisionless plasma. پرونده مقاله -
دسترسی آزاد مقاله
6 - Magnetized plasma sheath with two positive ions where collision frequencies have a power law dependency on ions velocities
S. Farhad Masoudi Mansor KhoramabadiAbstractWe study the dynamics of collisional magnetized plasma sheath with two species of positive ions by using the plasma fluid model. The basic equations of the fluid model are solved numerically where the sheath is in the external magnetic field and the elastic coll چکیده کاملAbstractWe study the dynamics of collisional magnetized plasma sheath with two species of positive ions by using the plasma fluid model. The basic equations of the fluid model are solved numerically where the sheath is in the external magnetic field and the elastic collision between ions and neutrals has been taken into account. In our model, we assume that the collisional momentum transferring cross section has a power law dependency on ion flow velocity. Our analysis demonstrates that the sheath dynamics are sensitive to the power law dependency, especially for the ion with greater density. پرونده مقاله
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