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Title: Turning point temperature and competition between relativistic and ponderomotive effects in self-focusing of laser beam in plasma

Journal Article · · Physics of Plasmas
DOI:https://doi.org/10.1063/1.4824455· OSTI ID:22218552
;  [1];  [2]
  1. Laser and Plasma Research Institute, Shahid Beheshti University, G.C., Tehran (Iran, Islamic Republic of)
  2. Plasma Physics Research School, Tehran (Iran, Islamic Republic of)

The propagation characters of Gaussian laser beam in collisionless plasma are investigated by considering the ponderomotive and relativistic nonlinearities. The second-order differential equation of dimensionless beam width parameter is solved numerically, taking into account the effect of electron temperature. The results show that the ponderomotive force does not facilitate the relativistic self-focusing in all intensity ranges. In fact, there exists a certain intensity value that, if below this value, the ponderomotive nonlinearity can contribute to the relativistic self-focusing, or obstruct it, if above. It is also indicated that there is a temperature interval in which self-focusing can occur, while the beam diverges outside of this region. In addition, the results represent the existence of a “turning point temperature” in the mentioned interval that the self-focusing has the strongest power. The value of the turning point is dependent on laser intensity in which higher intensities result in higher turning point.

OSTI ID:
22218552
Journal Information:
Physics of Plasmas, Vol. 20, Issue 10; Other Information: (c) 2013 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA); ISSN 1070-664X
Country of Publication:
United States
Language:
English