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Title: Ponderomotive acceleration of electrons in the interaction of arbitrarily polarized laser pulse with a tenuous plasma

Abstract

The forward ponderomotive force associated with an intense short laser pulse, propagating in a tenuous plasma, accelerates the electrons to velocities higher than the group velocity of the laser. In this work, a simple general solution for ponderomotive acceleration is presented for arbitrary polarization. The circular polarization is more efficient than linear polarization, since the threshold laser intensity needed for electron acceleration is lower for a circularly polarized laser pulse.

Authors:
; ;  [1];  [2];  [3]
  1. Physics Department and Laser-Plasma Research Institute of Shahid Beheshti University, Evin, 1983963113 (Iran, Islamic Republic of)
  2. (Iran, Islamic Republic of)
  3. (Iran, Islamic Republic of) and Institute for Studies in Theoretical Physics and Mathematics, P.O. Box 19395-3350, Tehran (Iran)
Publication Date:
OSTI Identifier:
20782567
Resource Type:
Journal Article
Resource Relation:
Journal Name: Physics of Plasmas; Journal Volume: 13; Journal Issue: 3; Other Information: DOI: 10.1063/1.2178187; (c) 2006 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
70 PLASMA PHYSICS AND FUSION TECHNOLOGY; ACCELERATION; BEAM-PLASMA SYSTEMS; ELECTRONS; LASER RADIATION; LASERS; LIGHT TRANSMISSION; NONLINEAR PROBLEMS; PLASMA; POLARIZATION; PONDEROMOTIVE FORCE; PULSES; VELOCITY

Citation Formats

Sazegari, V., Mirzaie, M., Shokri, B., Physics Department and Laser-Plasma Research Institute of Shahid Beheshti University, Evin, 1983963113, Tehran, and Physics Department and Laser-Plasma Research Institute of Shahid Beheshti University, Tehran. Ponderomotive acceleration of electrons in the interaction of arbitrarily polarized laser pulse with a tenuous plasma. United States: N. p., 2006. Web. doi:10.1063/1.2178187.
Sazegari, V., Mirzaie, M., Shokri, B., Physics Department and Laser-Plasma Research Institute of Shahid Beheshti University, Evin, 1983963113, Tehran, & Physics Department and Laser-Plasma Research Institute of Shahid Beheshti University, Tehran. Ponderomotive acceleration of electrons in the interaction of arbitrarily polarized laser pulse with a tenuous plasma. United States. doi:10.1063/1.2178187.
Sazegari, V., Mirzaie, M., Shokri, B., Physics Department and Laser-Plasma Research Institute of Shahid Beheshti University, Evin, 1983963113, Tehran, and Physics Department and Laser-Plasma Research Institute of Shahid Beheshti University, Tehran. Wed . "Ponderomotive acceleration of electrons in the interaction of arbitrarily polarized laser pulse with a tenuous plasma". United States. doi:10.1063/1.2178187.
@article{osti_20782567,
title = {Ponderomotive acceleration of electrons in the interaction of arbitrarily polarized laser pulse with a tenuous plasma},
author = {Sazegari, V. and Mirzaie, M. and Shokri, B. and Physics Department and Laser-Plasma Research Institute of Shahid Beheshti University, Evin, 1983963113, Tehran and Physics Department and Laser-Plasma Research Institute of Shahid Beheshti University, Tehran},
abstractNote = {The forward ponderomotive force associated with an intense short laser pulse, propagating in a tenuous plasma, accelerates the electrons to velocities higher than the group velocity of the laser. In this work, a simple general solution for ponderomotive acceleration is presented for arbitrary polarization. The circular polarization is more efficient than linear polarization, since the threshold laser intensity needed for electron acceleration is lower for a circularly polarized laser pulse.},
doi = {10.1063/1.2178187},
journal = {Physics of Plasmas},
number = 3,
volume = 13,
place = {United States},
year = {Wed Mar 15 00:00:00 EST 2006},
month = {Wed Mar 15 00:00:00 EST 2006}
}
  • The trapping and acceleration of an electron by forward ponderomotive force associated with intense short laser pulses, propagating in homogeneous rarefied plasmas is analyzed. This is done not by solving the motion equations but by energy conservation law and Lorentz transformation. This method is able to the treat the ponderomotive acceleration regardless of laser polarization. It is shown that the gain of acceleration increases linearly with the field strength of the laser and the relativistic factor of the group velocity of the laser in the plasma, while the minimum injection energy necessary for trapping the electron decreases with the lasermore » field strength and increases slowly with the group velocity of the laser.« less
  • Electron acceleration by a circularly polarized Gaussian laser pulse in magnetized plasma is investigated in the limit of frozen refractive index. The electron acceleration depends on the ratio of laser frequency to electron cyclotron frequency, amplitude of the laser pulse and plasma density. Near Doppler shifted cyclotron resonance the electron acquires maximum energy. In this scheme, 0.10 MeV electrons can be effectively accelerated to 1-100 MeV using moderate intensity laser pulse.
  • 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 pulse. As a result, pulse shape is distorted. An electron initially on the laser axis and at the front of the self-focusing pulse gains energy from the pulse until it is run over by the pulse peak. By the time electron reaches the tail, if pulse begins diverging, the deceleration of the electron is slower and the electron is leftmore » with net energy gain. The electrons slightly off the laser axis see a radial ponderomotive force too. Initially, when they are accelerated by the pulse front the acceleration is strong as they are closer to the axis. When they see the tail of the pulse (after being run by the pulse), they are farther from the axis and the retardation ponderomotive force is weaker. Thus, there is net energy gain.« less
  • The results of analytical treatment and computer simulation of the interaction between the relativistically strong electromagnetic field of an ultrashort laser pulse and a highly inhomogeneous overdense plasma are presented. {open_quotes}Vacuum heating of electrons,{close_quotes} i.e., formation of a cloud of fast electrons that is expanding into vacuum is the primary mechanism responsible for electromagnetic energy absorption under the oblique incidence of an electromagnetic wave upon dense plasma with a sharp boundary. It is shown that, in the electron cloud expanding into vacuum, ions are accelerated up to the energies corresponding to the equality of ion and fast electron velocities. 30more » refs., 6 figs.« less
  • The ponderomotive force at the front of an intense short pulse laser, propagating through a plasma, strongly influences the acceleration of electrons by a plasma wave or by the laser itself via betatron resonance in self-generated azimuthal magnetic field. It can enhance the electron energy gain several fold through the sustainment of the electron in the accelerating phase of the plasma wave and the laser beam.