Measurements of the Inverse Faraday Effect from Relativistic Laser Interactions with an Underdense Plasma

Z. Najmudin (1) , M. Tatarakis (1) , A. Pukhov (2) , E. L. Clark (1) , R.J. Clarke (3) , A.E. Dangor (1) , Jérôme Faure (4) , Victor Malka (4) , D. Neely (3) , M. I. K. Santala (1) , K. Krushelnick (1)

1 Blackett Laboratory
2 MPQ - Max-Planck-Institut für Quantenoptik
3 CLF - Central Laser Facility
4 LULI - Laboratoire pour l'utilisation des lasers intenses

Magnetic fields in excess of 7 MG have been measured with high spatial and temporal precision during interactions of a circularly polarized laser pulse with an underdense helium plasma at intensities up to 1×10^19Wcm^-2. The fields, while of the form expected from the inverse Faraday effect for a cold plasma, are much larger than expected, and have a duration approaching that of the high intensity laser pulse ( <3psec). These observations can be explained by particle-in-cell simulations in 3D. The simulations show that the magnetic field is generated by fast electrons which spiral around the axis of the channel created by the laser field.

Domaines: Optique [physics.optics]

Z. Najmudin, M. Tatarakis, A. Pukhov, E. L. Clark, R.J. Clarke, et al.. Measurements of the Inverse Faraday Effect from Relativistic Laser Interactions with an Underdense Plasma. Physical Review Letters, 2001, 87 (21), pp.215004. ⟨10.1103/PhysRevLett.87.215004⟩. ⟨hal-00520546⟩