ESS5
Prof.
Jin-Yi Yu
Step Leaders
qThe dry air is a good
electrical insulator, so a flow of
current can not occur.
q For cloud-to-ground lightning to occur, a stepped-leader must emanate from the cloud
base.
qThe leader is
essentially an ionized particle chamber about
10 cm (4 in) in diameter which forks
repeatedly from a main
channel.
qEach section travels
about 50 m in a microsecond.
qThe sections continue
until contact is made with an unlike
charged area (the ground).
