Modeling of clusters in a strong248‐nmlaser field by a three-dimensional relativistic molecular dynamic model

Abstract

A relativistic time-dependent three-dimensional particle simulation model has been developed to study the interaction of intense ultrashort KrF (248 nm) laser pulses with small Xe clusters. The trajectories of the electrons and ions are treated classically according to the relativistic equation of motion. The model has been applied to a different regime of ultrahigh intensities extending to 10(21) W/ cm(2). In particular, the behavior of the interaction with the clusters from intensities of approximately 10(15) W/cm(2) to intensities sufficient for a transition to the so-called "collective oscillation model" has been explored. At peak intensities below 10(20) W/cm(2), all electrons are removed from the cluster and form a plasma. It is found that the "collective oscillation model" commences at intensities in excess of 10(20) W/cm(2), the range that can be reached in stable relativistic channels. At these high intensities, the magnetic field has a profound effect on the shape and trajectory of the electron cloud. Specifically, the electrons are accelerated to relativistic velocities with energies exceeding 1 MeV in the direction of laser propagation and the magnetic field distorts the shape of the electron cloud to give the form of a pancake.

Intense ultrashort laser–Xe cluster interaction

“…As the cluster size is increased, less random motions are generated, and the Doppler broadening of the line emissions goes down and the calculated gains from Eqs. (2) and (3) go up. The cluster spherical expansion will also produce Doppler shifts of the lines, but these have not been computed.…”

“…On the other hand, atomic or molecular clusters are targets with unique properties that are midway between solids and gases and that combine the advantages of both. Clusters absorb much more energy compared to gases [1,2], and they offer a flexibility not found in solid targets. In essence, clusters can provide optimal conditions for laser energy absorption, for creation of highly charged ions, and for coherent short-wavelength X-ray emission.…”

Study of x-rays produced from debris-free sources with Ar, Kr and Kr/Ar mixture linear gas jets irradiated by UNR Leopard laser beam with fs and ns pulse duration

“…Interaction of short laser pulses with Ar and Kr clusters was modeled using a 3D relativistic molecular dynamics (MD) code [27,28]. The model accounts for plasma formation within the cluster, coupling of laser energy to the plasma and plasma evolution.…”

Influence of Xe and Kr impurities on x-ray yield from debris-free plasma x-ray sources with an Ar supersonic gas jet irradiated by femtosecond near-infrared-wavelength laser pulses

“…A 3D relativistic Molecular Dynamics (MD) code [16,17] was used for modeling the interaction of fs laser pulses with Xe clusters. The plasma formation within the cluster, coupling of laser energy to the plasma, and plasma evolution are all intricate parts of the model.…”