Ponderomotive force
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In physics, a ponderomotive force is a nonlinear force that a charged particle experiences in a rapidly oscillating, inhomogeneous electric or electromagnetic field. The ponderomotive force Fp is expressed by
where e is the electrical charge of the particle, m is the mass, ω is the frequency of oscillation of the field, and E is the amplitude of the electric or electromagnetic field. This equation means that an electron in an inhomogeneous oscillating field not only oscillates at the frequency of ω but also drifts toward the weak field area.
The mechanism of the ponderomotive force can be understood easily by considering the motion of the charge in an oscillating electric field. In the case of a homogeneous field, the charge returns to its initial position after one cycle of oscillation. In contrast, in the case of an inhomogeneous field, the position that the charge reaches after one cycle of oscillation shifts toward the lower field-amplitude area since the force imposed onto the charge at the turning point with a higher field amplitude is larger than that imposed at the turning point with a lower field amplitude, thus producing a net force that drives the charge toward the weak field area.
[edit] See also
[edit] References
Schmidt, George (1979). Physics of High Temperature Plasmas, second edition. Academic Press, p.47. ISBN 0-12-626660-3.
