Interaction between energetic electrons and a circularly
polarized laser pulse in a relativistic plasma channel
is studied. Laser radiation can be resonantly absorbed
by electrons executing betatron oscillations in the channel
and absorbing angular momentum from the laser. The absorbed
angular momentum manifests itself as a strong axial magnetic
field (inverse Faraday effect). The magnitude of this magnetic
field is calculated and related to the amount of the absorbed
energy.
Inverse Faraday effect from the orbital angular momentum of light