6 research outputs found
The use of relativistic action in strong-field nonlinear photoionization
Nonlinear relativistic ionization phenomena induced by a strong linearly
polarized laser field are considered. The starting point is the classical
relativistic action for a free electron moving in the electromagnetic field
created by a strong laser beam. This action has been used to calculate
semiclassical transition rates. Simple analytical expressions for the
ionization rate, the photoelectron emission velocity and for the drift momentum
distribution of the photoelectron have been found. The analytical formulas
apply to nonrelativistic bound systems as well as to initial states with an
energy corresponding to the upper boundary of the lower continuum and to the
tunnel as well as the multiphoton regime. In the case of a nonrelativistic
bound system we recover the Keldysh formula for the ionization rate.
Relativistic effects in the initial state lead to a weak enhancement of the
rate of sub-barrier ionization and to the appearance of a nonzero photoelectron
leaving velocity.Comment: 6 pages, 2 figure
Relativistic semiclassical approach in strong-field nonlinear photoionization
Nonlinear relativistic ionization phenomena induced by a strong laser
radiation with elliptically polarization are considered. The starting point is
the classical relativistic action for a free electron moving in the
electromagnetic field created by a strong laser beam. The application of the
relativistic action to the classical barrier-suppression ionization is briefly
discussed. Further the relativistic version of the Landau-Dykhne formula is
employed to consider the semiclassical sub-barrier ionization. Simple
analytical expressions have been found for: (i) the rates of the strong-field
nonlinear ionization including relativistic initial and final state effects;
(ii) the most probable value of the components of the photoelectron final state
momentum; (iii) the most probable direction of photoelectron emission and (iv)
the distribution of the photoelectron momentum near its maximum value.Comment: 13 pages, 3 figures, to be published in Phys. Rev.
Dielectric tensor and electromagnetic modes in magnetized non-ideal plasmas
This publication is with permission of the rights owner freely accessible due to an Alliance licence and a national licence (funded by the DFG, German Research Foundation) respectively.The effect of Coulomb correlations on the spectrum of electromagnetic waves propagating in a non-ideal magnetized fully ionized hydrogen plasma is studied. We employ the dielectric tensor constructed by means of the classical theory of moments without using perturbation theory.Peer Reviewe