Theory of Thomson Scattering of Partially Coherent Laser Probes in Plasmas

• Author / Creator

  Javan Roshtkhari, Mehraveh

• The effect of partial coherence of a probe on the spectrum of Thomson scattered radiation from plasma is investigated. The coherence of a probe is described in terms of the electric field Gaussian correlation function of the finite correlation time (longitudinal coherence) and the finite correlation length (transverse coherence). The Thomson scattering cross section is defined using dynamical form factor, i.e. Fourier transformed correlation function of electron density fluctuations. Two limiting cases of spatial (very large correlation length) and temporal (very long correlation time) coherence are considered. Thomson spectra of scattered radiation are calculated for these two cases and analyzed in the regime of collective plasma response dominated by ion-acoustic and Langmuir wave fluctuations. Partial coherence of the probe (finite coherence time and length) alters the scattered spectrum significantly. Two examples are discussed for each case by varying these two parameters of the correlation function. Finally, using inverse Fourier transforms, a theory is developed to show the possibility of recovering ion acoustic fluctuation spectrum from the scattered light spectrum of the partially coherent pump.

• Subjects / Keywords

  • Partial Coherence
  • Thomson Scattering
  • Plasma Diagnostics
  • Plasma

• Graduation date

  Spring 2017

• Type of Item

  Thesis

• Degree

  Master of Science

• DOI

  https://doi.org/10.7939/R3M61C25R

• License

  This thesis is made available by the University of Alberta Libraries with permission of the copyright owner solely for non-commercial purposes. This thesis, or any portion thereof, may not otherwise be copied or reproduced without the written consent of the copyright owner, except to the extent permitted by Canadian copyright law.