A Case for Submicrosecond Rise-Time Lightning Current Pulses for Use in Aircraft Induced-Coupling Studies

Recent measurements of lightning return stroke currents made using both direct and indirect techniques are reviewed and summarized. The data indicate that return stroke current pulses exhibiting submicrosecond rise times are common. Slower rise times reported previously may have been due to instrumentation limitations and, in some cases, to the investigator's definition of rise time. The earlier measurements led to the 2 x 50-microsecond current waveform which is the basis for lightning simulation specifications used in the aerospace industry. Laboratory induced-coupling studies and theoretical considerations are reported which indicate that, for aircraft work, use of the traditional 2x50-microsecond waveform represents inadequate testing, since the more realistic, faster pulses contain frequency components in the range of aircraft system resonances.