Investigation of laser-irradiated Ar cluster dynamics from K-shell x-ray emission measurements

Fabien Dorchies (1) , Tony Caillaud (1) , Frédéric Blasco (1) , Christophe Bonté (1) , Hervé Jouin (1) , Samuel Micheau (1) , Bernard Pons (1) , Jurgen Stevefelt (1)

1 CELIA - Centre d'Etudes Lasers Intenses et Applications

Intense (up to a few 1017 W/cm2) femtosecond (down to 40 fs) laser pulses are focused onto a partially clusterized Argon gas jet. The target was previously characterized and optimized in order to get a homogeneous and dense jet of clusters with a well controlled size. The interaction leads to x-ray emission that is absolutely calibrated and spectrally resolved using a high resolution timeintegrated spectrometer in the K-shell range (from 2.9 to 4.3 keV). X-ray spectra are investigated as a function of di_erent laser temporal parameters such as the nanosecond pre-pulse contrast, the laser pulse duration, and the femtosecond delay between two di_erent laser pulses. The cluster size ranges from 180 to 350 °A and irradiation by laser pulses with both linear and circular polarization is investigated. The experimental results are discussed in terms of the laser-cluster interaction dynamics. They are compared with the predictions of collision-dominated nano-plasma models. However, further interaction processes are required in order to explain the observed characteristic lines demonstrating highly charged ions up to Ar16+.

Domaines: Physique des plasmas [physics.plasm-ph]

Fabien Dorchies, Tony Caillaud, Frédéric Blasco, Christophe Bonté, Hervé Jouin, et al.. Investigation of laser-irradiated Ar cluster dynamics from K-shell x-ray emission measurements. Physical Review E : Statistical, Nonlinear, and Soft Matter Physics, 2005, 71, pp.066410-1. ⟨10.1103/PhysRevE.71.066410⟩. ⟨hal-00018361⟩