Early phases of lightning currents

The patterns of current waves of negative downward lightning strokes measured at the base of a short instrumented tower are discussed. The features of the current waveforms are commented specifically in relation to the early phase preceding the flow of the return current. Original data of currents measured recently in Brazil is presented to illustrate the specific patterns of first and subsequent strokes and of attempted leaders. Such patterns were commented in relation to those of distant electric fields previously reported in literature.