Electron heating of the cluster plasma by an ultrashort laser pulse

The interaction of an ultrashort ($\sim10$ fs) laser pulse with a relativistic intensity ($\gtrsim10^ {18}$ W/cm$^2$) with a cluster medium characterized by a random distribution of large, submicron clusters of heavy atoms has been studied. Matching conditions for the parameters of the cluster medium and the laser pulse have been determined under which the yield of hot electrons is maximal at a given laser energy. The stochastic dynamics of laser-heated electrons in the Coulomb fields of clusters after the passage of the pulse determines the formation of a plateau with signatures of quasimonochromaticity in the energy spectrum of electrons in the ponderomotive energy range, which is important for the generation of the secondary electromagnetic radiation.