Early streamer emission enhanced air terminal performance and zone of protection

An experimental study of the performance of ionizing air terminals versus nonionizing air terminals for lightning protection is reported. Radioactive sources are used to obtain ionization of the air surrounding the tip of the air terminals. Ionization due to field amplification by the geometrical shape is included. All the tests are performed on a comparison basis in which an enhanced air terminal is compared directly with a nonenhanced air terminal of the same geometry, or against a standard rod (Franklin air terminal). The test results indicate a substantial, superiority for the enhanced air terminal. Zone of protection is also defined, and is based on an electrogeometric model, including enhanced flexible dynamic length.<>