Work

Lateral Negative Re‐Discharges on the Negative Leader in a Positive Cloud‐to‐Ground Lightning Flash

Year: 2025

Type: article

Abstract: Negative‐polarity lateral discharges on pre‐ionized negative channels during a positive cloud‐to‐ground lightning flash were captured by very high frequency interferometric observations. Prior to the return stroke (RS), as the positive leader (PL) advanced steadily and the negative leader (NL) weakened, flickering lateral re‐discharges with small scale, resembling needles on PLs, propagated toward the NL tip at approximately 8.0 × 10 4 m/s. Unlike needles concentrated near PL tips, these re‐discharges occurred along nearly the entire horizontal negative channel. Following the RS, both fast discharges along existing negative channels and new lateral discharges breaking into virgin air were observed, rapidly extending the negative channels and sustaining the continuing current. These re‐discharges appeared to be closely linked to channel potential variations: gradual potential changes before the RS reactivation preceded negative branches, while abrupt potential jumps after the RS initiation triggered intense axial and lateral discharges.

Source: Geophysical Research Letters

DOI: 10.1029/2025gl117167