Photographer: C. Clark
Credit: NOAA Photo Library, NOAA Central Library

The term lightning is used to describe the phenomena associated with the discharge of electricity between a cloud and the ground, or between clouds.

Lightning is important for EMC because it :-

• Involves the transfer of large amounts of energy (of order 10¹⁰J).
• Generates high rates of change of current (di/dt) which cause strong induction effects on nearby systems.
• Generates high peak current which may cause melting and other mechanical damage to systems in the path.
• Affects large physical areas.
• Can happen almost anywhere on earth.