  Results are reported of an experiment performed at the Eclipse laser facility
in CELIA, Bordeaux, on the generation of strong electromagnetic pulses.
Measurements were performed of the target neutralization current, the total
target charge and the tangential component of the magnetic field for the laser
energies ranging from 45 mJ to 92 mJ with the pulse duration approximately 40
fs, and for the pulse durations ranging from 39 fs to 1000 fs, with the laser
energy approximately 90 mJ. It was found that the values obtained for thick (mm
scale) Cu targets are visibly higher than values reported in previous
experiments, which is argued to be a manifestation of a strong dependence of
the target electric polarization process on the laser contrast and hence on the
amount of preplasma. It was also found that values obtained for thin
(micrometer scale) Al foils were visibly higher than values for thick Cu
targets, especially for pulse durations longer than 100 fs. The correlations
between the total target charge versus the maximum value of the target
neutralization current, and the maximum value of the tangential component of
the magnetic field versus the total target charge were analysed. They were
found to be in very good agreement with correlations seen in data from previous
experiments, which provides a good consistency check on our experimental
procedures.
