Intense Laser Electric Fields Research Articles

Enhanced long-distance transport of periodic electron beams in an advanced double layer cone-channel target

An enhanced long-distance transport of periodic electron beams in an advanced double layer cone-channel target is investigated using two-dimensional particle-in-cell simulations. The target consists of a cone attached to a double-layer hollow channel with a near-critical-density inner layer. The periodic electron beams are generated by the combination of ponderomotive force and longitudinal laser electric field. Then a stable electron propagation is achieved in the double-layer channel over a much longer distance without evident divergency, compared with a normal cone-channel target. Detailed simulations show that the much better long-distance collimation and guidance of energetic electrons is attributed to the much stronger electromagnetic fields at the inner wall surfaces. Furthermore, a continuous electron acceleration is obtained by the more intense laser electric fields and extended electron acceleration length in the channel. Our investigation shows that by employing this advanced target, both the forward-going electron energy flux in the channel and the energy coupling efficiency from laser to electrons are about threefold increased in comparison with the normal case.

Dynamics of electronic motion in hydrogen atom under parallel strong oscillating magnetic field and intense laser fields

The mechanism of ionization of an H atom interacting with intense laser electric fields is altered when a strong, oscillating magnetic field is applied along a direction parallel to the laser field. In this first study, these two strongly nonperturbative situations have been combined together and the corresponding time‐dependent (TD) Schrödinger equation has been numerically solved without using any basis set. The electric field arising out of the magnetic field and the magnetic field arising out of the laser electric field are found to be negligibly small, thereby not affecting the results. There are two main, apparently counter‐intuitive results from this study of parallel fields of the same frequency but different field strengths: (1) In presence of an oscillating magnetic field, the ionization rate due to the laser field diminishes, and (2) increasing the laser intensity, keeping the magnetic field strength the same, makes the electron density ionize with a lesser rate, in contrast to the situation with intense lasers in the absence of a strong TD magnetic field. © 2015 Wiley Periodicals, Inc.

High-Order Harmonic Generation in Dense Plasmas with a High Intensity Light Field

High-order harmonic generation by an oscillating current due to intense laser electric fields in dense plasmas is investigated. In solid target plasmas produced by an intense ultra-short pulse laser, the intense laser radiation directly interacts with overdense plasmas. In such a case, plasma screening effects are important in the plasma response to the laser field. For such plasmas, the higher harmonics are evaluated by using a dynamical form factor for plasma electrons and ions. There is a peak in the harmonic spectrum at twice the plasma frequency.