An electromagnetic pulse (commonly abbreviated as EMP, pronounced /iː.ɛm.piː/) is a burst of electromagnetic radiation. Nuclear explosions create a characteristic pulse of electromagnetic radiation called a nuclear EMP or NEMP. The resulting rapidly changing electric and magnetic fields may couple with electrical and electronic systems to produce damaging current and voltage surges. The specific characteristics of any particular nuclear EMP event vary according to a number of factors, the most important of which is the altitude of the detonation.