Lightning strikes the earth, on average, more than 100 times each second. The typical lightning stroke is six miles long. The temperature of the return stroke, or primary flash, can reach 50,000°F, or nearly five times hotter than the surface of the sun. Property losses from lightning total in the hundreds of millions of dollars each year in the commercial and private sectors alone. Losses to military facilities and equipment are equally high and can only be expected to rise as semiconductor devices, which are inherently more susceptible to lightning effects, are increasingly used in military equipment. To facilitate the study and mitigation of this devastatingly powerful natural phenomenon, WSMR has installed a Lightning Test Facility (LTF) to simulate the direct and indirect effects of lightning strikes.
Direct effects of lightning include burning, eroding, blasting, and structural deformation caused by lightning arc attachment, as well as by the high-pressure shock waves and magnetic forces produced by the associated high currents. Indirect lightning effects are predominantly those resulting from the interaction of the electromagnetic fields accompanying lightning with electrical devices.
Working with the LTF, WSMR engineers have developed a lightning effects test capability in accordance with MIL STD-1757A, which establishes standards for the waveforms used to determine direct and indirect effects of lightning strikes.