Stieltjes-Tchebycheff Moment-Theory Approach to Molecular Photoionization Studies

1979 ◽  
pp. 183-224 ◽  
Author(s):  
P. W. Langhoff
Keyword(s):  
Theory Approach ◽  
Moment Theory ◽  
Molecular Photoionization

Enhanced Brillouin scattering of gaussian laser beam in collisional plasma: Moment theory approach

2014 ◽  
Vol 23 (01) ◽  
pp. 1450011 ◽  
Author(s):  
Keshav Walia
Keyword(s):  
Acoustic Wave ◽  
Laser Beam ◽  
Pump Beam ◽  
Brillouin Scattering ◽  
Scattered Wave ◽  
Theory Approach ◽  
Gaussian Laser Beam ◽  
Moment Theory ◽  
Ion Acoustic Wave ◽  
Ion Acoustic

In the present paper, enhanced Brillouin scattering of a gaussian laser beam in a collisional plasma has been investigated with the help of moment theory approach. The pump wave (ω0, k0) interacts with pre-excited ion-acoustic wave (ω, k), thereby generating a back-scattered wave (ω0 - ω, k0 - k). As a specific case, back scattering for which k ≃ 2k0 has been discussed. Due to nonuniform heating, collisional nonlinearity arises, which leads to redistribution of carriers. As a result background plasma density profile in a direction transverse to pump beam axis is modified. Consequently, the pump beam becomes self-focused and in turn leads focusing of ion-acoustic wave and back-scattered wave under appropriate conditions. It is further observed from the analysis that focusing of waves greatly enhances the SBS back-reflectivity.

scholarly journals Relativistic guidance of an intense laser beam through an axially non-uniform plasma channel

2011 ◽  
Vol 29 (3) ◽  
pp. 291-298 ◽  
Author(s):  
Arvinder Singh ◽  
Navpreet Singh
Keyword(s):  
Laser Pulse ◽  
Laser Beam ◽  
Plasma Channel ◽  
Nonlinear Differential Equations ◽  
Beam Width ◽  
Intense Laser ◽  
Theory Approach ◽  
Laser Guidance ◽  
Moment Theory ◽  
Uniform Plasma

AbstractThe effect of relativistic nonlinearity on the guiding of a laser beam in a plasma channel formed by a short ionizing pulse is investigated. The plasma channel formed is axially non-uniform due to self defocusing of the prepulse. When a second delayed laser pulse propagates through the plasma channel formed by the prepulse, the competition between refraction and diffraction results into alternate convergence and divergence of the guided beam. Second-order nonlinear differential equations for the beam width parameter of the prepulse and guided pulse are derived by moment theory approach. The effect of the guided pulse intensities as well as the axial nonuniformity of the plasma channel on the propagation of the guided laser pulse has been investigated. Relativistic laser guidance up to several Rayleigh lengths is observed.

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