Intense Magnetic Fields Generation in Laser Produced Plasma Using Inverse Faraday Effect

• Author / Creator

  Liza, Fatema TJ

• Laser plasma interactions with high intensity laser pulses can produce extremely high magnetic fields in the MG range. In particular, the application of circularly polarized or orbital angular mode (OAM) laser beams can be used to generate such large fields using the Inverse Faraday Effect (IFE). Inverse Faraday Effect is the phenomenon where a magnetic field is induced in the dielectric medium due to the rotation of the electromagnetic fields. These induced high magnetic fields in the MG range can play an important role in the generation and guiding of electrons in laser plasma interaction process. Hot electron generation due to the interaction of intense laser pulses with underdense plasma can generates additional axial and azimuthal currents also leading to generation of strong magnetic fields. Plasma interaction has been studied using Large Scale PIC (LSP) simulations to predict the scaling laws for the hot electron generation and hence the expected magnetic field for circularly polarized light. Simulations have been carried out for different densities (ne ≈0.0002 nc to ne ≈0.02 nc) and intensities in the threshold relativistic intensity range of 1017 to 1019 Wcm-2 . Simulation results show that the induced magnetic fields vary with both electron density and laser intensity and the hot electron generation depends on laser intensity too. Multiple scaling laws proposed by different authors are compared with the simulation results. A Scaling law that takes the spiralling hot electron current into account is the one that appears to agree best with the simulation results. In order to measure these expected intense fields Zeeman splitting of emission lines is investigated as a means to measure the induced axial magnetic fields. A Preliminary set of measurements have carried to verify the measurements of emission lines from the focusing into static gas targets at modest intensities of the order of 1017 Wcm-2. CO2 is used as the background gas and emission lines of CII 657.8nm and CII 658.3nm were measured for the linearly and circularly polarized laser beams. With the available laser power, 1GW, the Induced magnetic fields are fairly small and it was not possible to measure the splitting. However, scaling to higher irradiation powers should allow measurable magnetic fields to be observed.

• Subjects / Keywords

  • Plasma
  • Laser

• Graduation date

  Fall 2016

• Type of Item

  Thesis

• Degree

  Master of Science

• DOI

  https://doi.org/10.7939/R3CV4BX2M

• 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.