Raw image plate data taken at (a) GXII PW at Osaka University and (b) the VULCAN PW laser at RAL. In both cases, electron spectrometers were put on the laser axis and the collimator size was fixed at . Laser intensities and targets were (a) and Al thickness and (b) and Cu thickness.
Typical calibrated electron spectra taken from the data in Fig. 1. Signals are indicated as dots. Line embedded in the signals indicates fitting with a relativistic Maxwellian equation (1). The background noise level is also indicated.
Plot of the measured electron temperature as a function of intensity on target. Also plotted is the ponderomotive potential energy as dotted line. A least square fit to the data as line shows that the fast electron temperature scales as .
Vlasov simulations of the fast electron energy distribution calculated into the interaction of a flat top laser pulse incident onto a plasma slab with a small density scale length. The bulk temperature is consistent with that expected with a 20% absorption fraction.
Plot of the experimental fast electron temperature (normalized to ) vs shown as dots. Also shown is the ponderomotive potential energy as dotted line (Ref. 11) and Haines’ relativistic model as line (Ref. 30).
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