In the double-cone ignition scheme of inertial confinement fusion, the head-on collision of two compressed fuel jets from the cone-tips forms an isochoric plasma, which is then heated suddenly by a MeV relativistic electron beam produced by ultra-intense picosecond laser pulses. This fast-heating process was studied experimentally at the Shenguang II upgrade laser facility. By observing temporal-resolved X-ray emission and the spatial-resolved X-ray spectrum, the colliding process and heating process are carefully studied. The colliding plasma was imaged to have dimensions of approximately 86 μm in the implosion direction and approximately 120 μm in the heating direction. By comparing the simulated plasma X-ray spectrum with experimental data, the electron temperature of the heated plasma was found to rapidly increase to 600 ± 50 eV, almost doubling the temperature achieved before the heating laser incidence.

The chlorine Heα radiation of polyvinyl chloride (PVC) was investigated with respect to X-ray scattering experiments on dense plasmas. The X-ray source was a laser-produced plasma that was observed with a highly reflective highly oriented pyrolytic graphite (HOPG) crystal spectrometer as it is used in current x-ray scattering experiments on dense plasmas. The underlying dielectronic satellites of Heα cannot be resolved, therefore the plasma was observed at the same time with a focusing spectrometer with spatial resolution. To reconstruct the spectrum a simple model to calculate the spectral line emission based on dielectronic recombination and inner shell excitation of helium- and lithium-like ions was used. The analysis shows that chlorine dielectronic satellite emission is intense compared to Heα in laser-produced chlorine plasmas with a temperature of 300 eV in this wavelength range of Δλ = 0.07 Å (ΔE = 43 eV). The method proposed in this paper allows deducing experimentally the role of the underlying dielectronic satellites in the scatter spectrum measured with a HOPG crystal spectrometer. It is shown that the dielectronic satellites can be neglected when the scattering is measured with low spectral resolution in the non-collective regime. They are of major importance in the collective scatter regime where a high spectral resolution is necessary.

The dynamics of the expansion plasma produced by excimer laser ablation of a silicon target into oxygen and mixed O2/Ar atmosphere were studied by means of time-resolved imaging of the expanding plume. Experiments were performed in pure oxygen, ranging between 0.13 and 13.33 Pa, and at different O2/Ar ratios at a fixed total pressure of 13.33 Pa. The occurrence of a shock wave (SW) generated by the supersonic expansion of the plasma was observed at high pressure values. The presence of the SW had a strong influence on the structure of SiOx thin films. In fact, silicon dioxide thin films were always obtained in presence of the SW, irrespective of the oxygen content in the gaseous mixture. On the contrary, suboxide thin films were obtained when the expansion occurred at lower pressure values (no SW presence). The temperature rise following the developing of the SW, is supposed to enhance the oxygen molecules dissociation by increasing the efficiency of the silicon oxidation reaction.