TITLE

Nonstationary ponderomotive self-focusing of a Gaussian laser pulse in a plasma

AUTHOR(S)
Tripathi, Deepak; Bhasin, Lalita; Uma, R.; Tripathi, V. K.
PUB. DATE
November 2010
SOURCE
Physics of Plasmas;Nov2010, Vol. 17 Issue 11, p113113
SOURCE TYPE
Academic Journal
DOC. TYPE
Article
ABSTRACT
A model of relaxing ponderomotive nonlinearity is developed to study the nonstationary self-focusing of a Gaussian laser pulse in a plasma. The ponderomotive force acts on the electrons instantaneously but the plasma density redistribution via the process of ambipolar diffusion is taken to evolve on the time scale τR≅r0/cs, where r0 is the laser spot size and cs is the sound speed. The paraxial ray approximation is used to solve the wave equation. The focusing is stronger at the rear of the pulse than at the front, causing considerable distortion of the pulse when pulse duration is comparable to nonlinearity relaxation time. The saturation effect of nonlinearity leads to focusing of any portion of the pulse to a minimum spot size r0fmin at an optimum distance zop and then the spot size increases. fmin and zop depend on the intensity of the portion of the pulse.
ACCESSION #
55509409

 

Related Articles

  • Plasma density gratings induced by intersecting laser pulses in underdense plasmas. Sheng, Z.-M.; Zhang, J.; Umstadter, D. // Applied Physics B: Lasers & Optics;Nov2003, Vol. 77 Issue 6/7, p673 

    Electron and ion density gratings induced by two intersecting ultrashort laser pulses at intensities of 10[sup 16] W/cm[sup 2] or lower are investigated. The ponderomotive force generated by the inhomogeneous intensity distribution in the intersecting region of the interfering pulses produces...

  • Group velocity and pulse lengthening of mismatched laser pulses in plasma channels. Schroeder, C. B.; Benedetti, C.; Esarey, E.; van Tilborg, J.; Leemans, W. P. // Physics of Plasmas;Aug2011, Vol. 18 Issue 8, p083103 

    Analytic solutions are presented to the non-paraxial wave equation describing an ultra-short, low-power, laser pulse propagating in a plasma channel. Expressions for the laser pulse centroid motion and laser group velocity are derived, valid for matched and mismatched propagation in a parabolic...

  • Spatiotemporal evolution of ponderomotive electron heating in axially inhomogeneous collisionless plasma. Mishra, S. K.; Sharma, A. // Physics of Plasmas;Jul2013, Vol. 20 Issue 7, p073109 

    We investigate the spatiotemporal focusing dynamics of a Gaussian laser pulse in preformed collisionless plasma subjected to an axial nonuniformity in the plasma density. In order to follow up the pulse dynamics, a nonlinear Schrödinger wave equation characterizing the beam spot size in space...

  • Filamentation of laser in a magnetized plasma under relativistic and ponderomotive nonlinearities. Singh, Ranjeet; Tripathi, V. K. // Physics of Plasmas;May2009, Vol. 16 Issue 5, p052108 

    Filamentation of a circularly polarized short pulse laser propagating along the direction of ambient magnetic field in plasma is studied. The nonlinearity arises through the combined effect of relativistic mass variation and ponderomotive force induced electron cavitation. The growth rate is...

  • Effect of nonlinear absorption on self focusing of short laser pulse in a plasma. Kumar, Ashok // Physics of Plasmas;Jun2012, Vol. 19 Issue 6, p063101 

    Paraxial theory of self focusing of short pulse laser in a plasma under transient and saturating effects of nonlinearity and nonlinear absorption is developed. The absorption is averaged over the cross-section of the beam and is different for different time segments of the pulse. The electron...

  • Soliton content of arbitrarily shaped light pulses in fibers analysed using a soliton-radiation beat pattern. Böhm, M.; Mitschke, F. // Applied Physics B: Lasers & Optics;Feb2007, Vol. 86 Issue 3, p407 

    Arbitrarily shaped light pulses propagating down a fiber may contain one or several solitons and a radiative background. A novel computer-assisted method is introduced to identify the composition. This technique does not suffer from restrictions of applicability to integrable systems. As an...

  • Self-focusing and channel-coupling effects on short laser pulses propagating in a plasma channel. Jha, Pallavi; Wadhwani, Navina; Upadhyaya, Ajay. K.; Raj, Gaurav // Physics of Plasmas;Jun2004, Vol. 11 Issue 6, p3259 

    Nonparaxial, nonlinear propagation of a relativistic laser pulse in a preformed plasma channel having a parabolic density profile is analyzed. Nonlinearity arises due to relativistic motion of plasma electrons and their coupling with plasma channel. The effect of nonlinearities on betatron...

  • Ponderomotive acceleration of electrons by a self focused laser pulse. Singh, Rohtash; Sharma, A. K. // Physics of Plasmas;Dec2010, Vol. 17 Issue 12, p123109 

    Ponderomotive acceleration of electrons by a short laser pulse undergoing relativistic self-focusing in a plasma is investigated. The saturation in nonlinear plasma permittivity causes periodic self-focusing of the laser. The periodicity lengths are different for different axial segments of the...

  • Ultra-Intense Laser Pulse Absorption and Fast Particles Generation at Interaction with Inhomogeneous Foil Target. Andreev, A. A.; Okada, T.; Toraya, S. // AIP Conference Proceedings;2002, Vol. 634 Issue 1, p303 

    The absorption of a short laser pulse with duration 40 fs and the intensity more than 10[SUP18] W/cm[SUP2] at the interaction with foil targets is analyzed in the theory and particle-in-cell (PIC) simulations. Initially, foil target density distribution has a smooth gradient with a variable...

Share

Read the Article

Courtesy of VIRGINIA BEACH PUBLIC LIBRARY AND SYSTEM

Sorry, but this item is not currently available from your library.

Try another library?
Sign out of this library

Other Topics