Recent experiments on electron transport in high-intensity laser matter interaction

We present the results of some recent experiments performed at the LULI laboratory using the 100 TW laser facility concerning the study of the propagation of fast electrons in gas and solid targets. Novel diagnostics have been implemented including chirped shadowgraphy and proton radiography. Proton radiography images did show the presence of very strong fields in the gas probably produced by charge separation. In turn these imply a slowing down of the fast electron cloud as it penetrates in the gas and a strong inhibition of propagation. Indeed chirped shadowgraphy images show a strong reduction in time of the velocity of the electron cloud from the initial value, which is of the order of a fraction of c. We also performed some preliminary experiments with cone targets in order to verify the guiding effect and fast electron propagation in presence of the cone. Finally we compared results obtained by changing the target size. Here we only give a first presentation and preliminary analysis of data, which will be addressed in detail in a following paper.