A High-altitude electromagnetic pulse of great magnitude can be explained in easier terms. A magnetic field can be created by using an electric current like in a simple AM/FM radio. The transmitter uses electric currents to send signals into the air, creating an electromagnetic field in which a receiver can decode. If the transmitter was to use larger current, then the field would be greater in strength and the receiver would have its components fried (How Stuff Works).

Using one of the most important concepts of physics, conservation of momentum, the Compton Effect explains how an electromagnetic pulse occurs and why it is more devastating at higher altitudes. If one were to throw a puck at another puck on an air hockey table, they would go off in different directions and slower speeds than the initial puck. The Compton Effect says, using the photon theory, that when photons traveling at incredibly high speeds collide with particles, electrons in the outer shells are knocked off (about.com:physics, the Compton Effect, by Andrew Zimmerman Jones). So the initial photon is like the first puck thrown and the particle it hits is the second. Once the photon collides, it goes in one direction and the electron that was knocked off goes in another as depicted in the picture to the right. The spreading of these electrons ionizes the air creating an electric field.

At a higher altitude, there are far less particles available to collide with allowing the radius of the electromagnetic pulse to become far greater before hitting the earth at ground level, where most of the electronic devices that are to be affected reside. Also, electrons are trapped easier in Earth’s magnetic fields between 20 and 40 km above earth (Federation of American Scientists). They oscillate very quickly and give way to the large electromagnetic pulse.