Figure 1.

(a) Low-density polymer foam with stochastic 3D structure⁴¹; (b) nanosecond pulse to convert the foam into a plasma, followed by a relativistic sub-ps pulse to accelerate the electrons; (c) experimental setup with magnetic spectrometers placed around the foam target; (d) spectra of the ponderomotive electrons in the case of a high contrast shot on the foam without ns-pulse; (e) measured energy and angular distribution of the DLA electrons in the case of pre-ionized foams; (f) generation of the synchrotron radiation in the relativistic plasma channel during the betatron oscillations of the DLA electrons.