POSSIBLE PRECURSORS OF BALL-LIGHTNING - OBSERVATION OF CLOSED LOOPS IN HIGH-VOLTAGE DISCHARGES

Several hundred photographs of ultrahigh voltage discharges have been obtained that show closed current loops. These closed current loops ma y be precursors of ball lightning. One feature of these discharges may explain why observations of ball lightning may be infrequent; that is , there is a distinct threshold in voltage and/or current below which the closed loops do not occur. This threshold current fits other exper imental data but is well above the usually observed currents in natura l lightning.