Article révisé par les pairs
Résumé : The process of high-order harmonic generation which was similar to the other two in arising from the same three-step mechanism was examined. It was found that the suppression was not severe, even for pondermotive energies well above 10 keV. Numerical results were also presented for high-order harmonic emission by a single Ne9+ ion moving with a Lorentz factor against a Nd:glass laser beam. The results show that the speed of the ions intervenes only through the Doppler effect, which makes it possible to detach electron from multicharged ions at high intensity.