[¦at·mə¦sfir·ik i¦lek·trik ′fēld] (geophysics) The atmosphere's electric field strength in volts per meter at any specified point in time and space; near the earth's surface, in fair-weather areas, a typical datum is about 100 and the field is directed vertically in such a way as to drive positive charges downward.AcronymsSeeAEF