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We discuss the generation of high-density and high-temperature plasmas by focusing high peak power laser radiation onto a solid target. Emphasis will be put on the process of laser ablation and on its basic, physical mechanisms. A survey will be given of the main experimental techniques, namely optical emission and absorption spectroscopy, mass spectrometry, time-of-flight and charge collection measurements, devised to characterize laser-produced plasmas. The fundamental theoretical and numerical approaches developed to analyse laser-target interaction, plasma formation, as well as its expansion will also be reviewed, and their predictions compared with the experimental findings. Although the main emphasis of the review will be on metal target ablation, reference and comparison to results on multicomponent targets will also be frequently given.

[1] A strategy for European Aerosol Research Lidar Network (EARLINET) correlative measurements for Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observation (CALIPSO) has been developed. These EARLINET correlative measurements started in June 2006 and are still in progress. Up to now, more than 4500 correlative files are available in the EARLINET database. Independent extinction and backscatter measurements carried out at high-performance EARLINET stations have been used for a quantitative comparison with CALIPSO level 1 data. Results demonstrate the good performance of CALIPSO and the absence of evident biases in the CALIPSO raw signals. The agreement is also good for the distribution of the differences for the attenuated backscatter at 532 nm ((CALIPSO-EARLINET)/EARLINET (%)), calculated in the 1-10 km altitude range, with a mean relative difference of 4.6%, a standard deviation of 50%, and a median value of 0.6%. A major Saharan dust outbreak lasting from 26 to 31 May 2008 has been used as a case study for showing first results in terms of comparison with CALIPSO level 2 data. A statistical analysis of dust properties, in terms of intensive optical properties (lidar ratios, Ångström exponents, and color ratios), has been performed for this observational period. We obtained typical lidar ratios of the dust event of 49 ± 10 sr and 56 ± 7 sr at 355 and 532 nm, respectively. The extinction-related and backscatter-related Ångström exponents were on the order of 0.15-0.17, which corresponds to respective color ratios of 0.91-0.95. This dust event has been used to show the methodology used for the investigation of spatial and temporal representativeness of measurements with polar-orbiting satellites.

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