Transient
De luz-wiki
The initial phase of an alternating field has played a minor role in the force exerted by the field over a free charge. The main reason being that in most cases the transient behaviour has a slowly varying envelope.
However, in recent times either with passive or active schemes, very short optical pulses have been achieved. These pulses may contain only a few oscillations and the slowly varying envelope condition is no longer fulfilled.
The external field is often set
Titles for the effect we are describing
charge scattering due to transient fields
