A directional hot electron jet with energy higher than 100 keV was generated along the laser propagation direction from Ar clusters irradiated with a laser pulse of duration 28 fs and intensity $1\times {10}^{17}\mathrm{W}/{\mathrm{cm}}^2.$ The hot electron jet was detected only with linearly polarized laser pulses, not with circularly polarized pulses. Channel betatron resonance is believed to be the main accelerating mechanism for this directional hot electron jet.

• Received 28 March 2002

DOI:https://doi.org/10.1103/PhysRevE.66.025402