Although collisions with charged particles also provide a strong electromagnetic perturbation (often in form of a short pulse as soon as the projectile velocity is large enough), the characteristics of the perturbing field are significantly different from those delivered by a laser pulse. While lasers provide (up to details) an electromagnetic field with a well defined frequency band (basically the laser frequency), collisions with charged projectiles deliver a perturbation covering a very broad band of frequencies, the broader the shorter the pulse. This delivers useful, complementing information to that attained from lasers. It is important to note that collisions with charged projectiles also concern a wide range of potential applications of irradiation dynamics, especially in relation to radiation damage and applications thereof. The present review concentrates on laser excitations. Nevertheless, we shall discuss a few cases with high energy projectiles. For them, the delivered electromagnetic perturbation can be modeled as an instantaneous boost ($\propto \delta(t)$) at the initial time of the simulation. This is the way we shall treat this case in the following (see in particular Sec. \[sec:projectile\]).

From integrated to detailed observables {#sec:observ}
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Electronic emission can be analyzed at various levels of sophistication, starting from fully integrated 