Ponderomotive acceleration of electrons by a whistler pulse

A Gaussian whistler pulse is shown to cause ponderomotive acceleration of electrons in a plasma when the peak whistler amplitude exceeds a threshold value and the whistler frequency is greater than half the cyclotron frequency, ω>ω _c /2. The threshold amplitude decreases with the ratio of plasma frequency to electron cyclotron frequency, ω _p /ω _c . However, above the threshold amplitude, the acceleration energy decreases with ω _p /ω _c . The electrons gain velocities about twice the group velocity of the whistler.