(Wikipedia Definition-The electromagnetic field (EMF) is composed of two related vectorial fields, the electric field and the magnetic field. This means that the vectors (E and B) that characterize the field each have a value defined at each point of space and time. If only E, the electric field, is nonzero and is constant in time, the field is said to be an electrostatic field.)
Paranormal investigators have found throughout the course of their research over the years that spirits manifest themselves by feeding off of energy. Many times at genuinely haunted locations batteries, and electrical equipment in general lose their "juice" very fast. This is why paranormal researchers pay close attention to certain weather conditions such as Solar-X Rays, Lunar Phases, and Geomagnetic storms.
When either solar flare activity or geomagnetic field activity spike there is an increase in natural atmospheric energy. So since spirits use energy they are more likely to be around when there is an abundance of it. The Moons positions also affect magnetic fields, so yes believe it or not, just like in the movies the full moon seems to get the paranormal ball rolling! So knowing all this you see why when a researcher sees a spike in their EMF equipment for no apparent reason there might just be a spirit afoot causing the energy disturbance.
