Molecular dynamics simulations of plasmas in electromagnetic fields : collisional absorption

Collisional absorption of dense fully ionized plasmas in strong laser fields has been investigated using molecular dynamics simulations [1, 2, 3]. The external electric field was implemented as a homogeneous linearly polarized harmonic field. The main difficulty in order to simulate a fully ionized plasma is to model the attractive electron–ion interaction: the pure Coulomb potential has a singularity at the origin which may cause some non–physical behaviour. Beside the simplest way to avoid this divergence – the so-called soft Coulomb potential – there are often used effective quantum potentials like the Kelbg potential or the Deutsch potential. The latter are temperature dependent via the thermal wavelength. In strong electric fields, the assumption of local thermodynamic equilibrium may not be fullfilled, there are attempts to use the DeBroglie wavelength including the quiver velocity instead of the thermal wavelength. Results for the different potentials are compared and discussed in [1, 2, 4, 5].