Filamentation instability of a laser beam in an inhomogeneous plasma in an arbitrarily oriented external magnetic field

2013 ◽  
Vol 79 (5) ◽  
pp. 921-926
Author(s):  
A. HASANBEIGI ◽  
A. MOUSAVI ◽  
H. MEHDIAN
Keyword(s):  
Magnetic Field ◽  
Growth Rate ◽  
External Magnetic Field ◽  
Laser Beam ◽  
Short Pulse ◽  
Inhomogeneous Plasma ◽  
Plasma Inhomogeneity ◽  
Short Pulse Laser ◽  
Filamentation Instability ◽  
Applied External Magnetic Field

AbstractThe interaction of a short pulse laser beam with an inhomogeneous plasma has been studied in the presence of an obliquely applied external magnetic field. The dispersion relation and the analytical growth rate have been obtained solving the nonlinear wave equation. It is found that the growth rate and the cut-off wavenumber are strongly influenced by the direction and magnitude of the applied magnetic field. Moreover, the growth rate has been modified by plasma inhomogeneity.

scholarly journals Brillouin backward scattering in the nonlinear interaction of a short-pulse laser with an underdense transversely magnetized plasma

2013 ◽  
Vol 31 (2) ◽  
pp. 313-319 ◽  
Author(s):  
Alireza Paknezhad
Keyword(s):  
Magnetic Field ◽  
Growth Rate ◽  
External Magnetic Field ◽  
Short Pulse ◽  
Propagation Direction ◽  
Magnetized Plasma ◽  
Third Order ◽  
Short Pulse Laser ◽  
Linearly Polarized ◽  
Temporal Growth Rate

AbstractBrillouin backward scattering is investigated in the interaction of linearly polarized short laser pulse with a homogenous underdense transversely magnetized plasma by taking into account the relativistic and nonlinearity effects up to third order. The plasma is embedded in a uniform magnetic field perpendicular to both of propagation direction and electric vector of the radiation field. Temporal growth rate of instability is calculated by using of the nonlinear wave equation. Results are significantly different in comparison with lower order computations. The growth rate of Brillouin backward instability shows a decrease due to the presence of external magnetic field, while relativistic and higher order nonlinearities due to the external magnetic field, give rise the Brillouin backward scattering instability.

scholarly journals Dynamics of UV short pulse laser-induced plasmas from a ceramic material “titanium carbide”: a hydrodynamical out of equilibrium investigation

2019 ◽  
Vol 37 (01) ◽  
pp. 86-100
Author(s):  
A. Ait Oumeziane ◽  
J-D. Parisse
Keyword(s):  
Laser Beam ◽  
Ceramic Material ◽  
Material Properties ◽  
Atmospheric Pressure ◽  
Short Pulse ◽  
Plume Expansion ◽  
Pure Material ◽  
Short Pulse Laser ◽  
Helium Gas ◽  
Ionization Rates

AbstractThe present work is motivated by the numerous applications of short lasers–ceramics interaction. It aims at applying a newly developed model to investigate the dynamic of laser-induced plasmas from a ceramic material into a helium gas under atmospheric pressure. To have a better understanding of the link between the material properties, the plume characteristics and its interaction with the laser beam, a thorough examination of the entire ablation processes is conducted. Comparison with the behavior of laser-induced plumes under the same conditions from a pure material is shown to have a key role in shedding the light on what monitors the plume expansion in the background environment. Plume temperatures, velocities, ionization rates as well as elemental composition have been presented and compared under carefully chosen relevant conditions. This study is of interest for laser matter applications depending on the induced plasmas dynamics and composition.

Filamentation instability in a collisional magnetoplasma with thermal conduction

2009 ◽  
Vol 75 (4) ◽  
pp. 563-573 ◽  
Author(s):  
MAHENDRA SINGH SODHA ◽  
MOHAMMAD FAISAL
Keyword(s):  
Magnetic Field ◽  
Growth Rate ◽  
Static Magnetic Field ◽  
Power Loss ◽  
Thermal Conduction ◽  
Ohmic Heating ◽  
Wave Number ◽  
Main Beam ◽  
Rate Of Growth ◽  
Filamentation Instability

AbstractThis paper presents an analysis of the spatial growth of a transverse instability, corresponding to the propagation of an electromagnetic beam, with uniform irradiance along the wavefront in a collisional plasma, along the direction of a static magnetic field; expressions have been derived for the rate of growth, the maximum value of the rate of growth and the corresponding value of the wave number of the instability. The instability arises on account of the ejection of electrons from regions where the irradiance of the perturbation is large. The energy balance of the electrons taking into account ohmic heating and the power loss of electrons on account of (i) collisions with ions and neutral species and (ii) thermal conduction has been taken into account for the evaluation of the perturbation in electron temperature, which determines the subsequent growth of the instability. Further, the relationship between the electron density and temperature, as obtained from the kinetic theory, has been used. The filamentation instability becomes enhanced with the increase of the static magnetic field for the extraordinary mode while the reverse is true for the ordinary mode. Dependence of growth rate on irradiance of the main beam, magnetic field and a parameter proportional to the ratio of power loss of electrons by conduction to that by collisions has been numerically studied and illustrated by figures. The dependence of the maximum growth rate and the corresponding optimum value of the wave number of the instability on the irradiance of the main beam has also been studied. The paper concludes with a discussion of the numerical results, so obtained.

Electron whistler mode instability in an inhomogeneous thermal plasma in the presence of an inhomogeneous beam of suprathermal electrons

1983 ◽  
Vol 29 (3) ◽  
pp. 439-448 ◽  
Author(s):  
H.A. Shah ◽  
V.K. Jain
Keyword(s):  
Magnetic Field ◽  
Growth Rate ◽  
Dispersion Relation ◽  
Thermal Plasma ◽  
Uniform Magnetic Field ◽  
Inhomogeneous Plasma ◽  
Mode Instability ◽  
Whistler Mode ◽  
Suprathermal Electrons ◽  
Whistler Mode Waves

The excitation of the whistler mode waves propagating obliquely to the constant and uniform magnetic field in a warm and inhomogeneous plasma in the presence of an inhomogeneous beam of suprathermal electrons is studied. The full dispersion relation including electromagnetic effects is derived. In the electrostatic limit the expression for the growth rate is given. It is found that the inhomogeneities in both beam and plasma number densities affect the growth rates of the instabilities.

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