Roles of the Quadrupole Interaction and of the Quadratic Stark Effect in Spectral Lines from Plasmas Interacting with a Strong Quasimonochromatic Electric Field

We present an advanced analysis of the spectroscopic signatures of the interaction of a strong Quasimonochromatic Electric Field (QEF), generated by a high-power short-pulse laser, with a preformed laser-produced plasma. The computation of a synthetic spectrum emitted by such plasmas requires the calculation of the Stark line shape in the presence of a QEF and the evaluation of the QEF intensity profile throughout the line of sight in the plasma. Stark profiles in hot dense plasmas containing a strong QEF are calculated using the so-called Floquet-Liouville formalism. In this paper, in distinction to our previous publications, we studied the roles of the quadrupole interaction with the ion microfield and of the quadratic Stark effect. Then Particle-In-Cell (PIC) kinetic simulations were performed for taking into account the inhomogeneity of the QEF intensity. These theoretical calculations were applied for a spectroscopic analysis of the experimental Al He β line. The spectroscopic signatures of the QEF are prominent satellites, non-symmetrical with respect to the unperturbed line and distinguishable from the dielectronic satellites. We found that the allowance for the quadratic Stark effect was important for the consistent interpretation of the experimental results, while the allowance for the quadrupole interaction with the ion microfield did not play a significant role. PACS: 52.38.-r, 32.70.-n, 52.70.-m, 32.60.+i.