  Electron dynamics in the bulk of large band gap dielectric crystals induced
by intense femtosecond laser pulses at 800 nm is studied. With laser
intensities under the ablation threshold (a few 10 TW/cm\textsuperscript{2}),
electrons with unexpected energies in excess of 40-50 eV are observed by using
the photoemission spectroscopy. A theoretical approach based on the Boltzmann
kinetic equation including state-of-the-art modeling for various particles
interactions is developed to interpret these experimental observations. A
direct comparison shows that both electron heating in the bulk and a further
laser field acceleration after ejection from the material contribute
equivalently to the final electron energy gain. The electron heating in the
bulk is shown to be significantly driven by a non-collisional process, i.e.
direct multiphoton transitions between sub-bands of the conduction band. This
work also sheds light on the contribution of the standard electron
excitation/relaxation collisional processes, providing a new baseline to study
the electron dynamics in dielectric materials and associated applications as
laser material structuring.
