isotropic radiation
英[aisəuˈtrɔpik ˌreidiˈeiʃən]美[ˌaɪsəˈtropɪk ˌrediˈeʃən]
Isotropic radiation has the same intensity regardless of the direction of measurement, and an isotropic field exerts the same action regardless of how the test particle is oriented. It radiates uniformly in all directions from a point source sometimes called an isotropic radiator.