Editing Lightning (section)

==== Discharge – Re-strike ====
High-speed videos (examined frame-by-frame) show that most negative CG lightning flashes are made up of 3 or 4 individual strokes, though there may be as many as 30.<ref>[[#Uman|Uman (1986)]] Ch. 5, p. 41.</ref>

Each re-strike is separated by a relatively large amount of time, typically 40 to 50 milliseconds, as other charged regions in the cloud are discharged in subsequent strokes. Re-strikes often cause a noticeable "[[strobe light]]" effect.<ref name="uman">[[#Uman|Uman (1986)]] pp. 103–110.</ref>

To understand why multiple return strokes utilize the same lightning channel, one needs to understand the behavior of positive leaders, which a typical ground flash effectively becomes following the negative leader's connection with the ground. Positive leaders decay more rapidly than negative leaders do. For reasons not well understood, bidirectional leaders tend to initiate on the tips of the decayed positive leaders in which the negative end attempts to re-ionize the leader network. These leaders, also called ''recoil leaders'', usually decay shortly after their formation. When they do manage to make contact with a conductive portion of the main leader network, a return stroke-like process occurs and a ''dart leader'' travels across all or a portion of the length of the original leader. The dart leaders making connections with the ground are what cause a majority of subsequent return strokes.<ref name="Warner">{{cite web |url=https://ztresearch.blog/education/ground-flashes/ |title=Ground Flashes |last=Warner |first=Tom |website=ZT Research |access-date=November 9, 2017|date=May 6, 2017 }}</ref>

Each successive stroke is preceded by intermediate dart leader strokes that have a faster rise time but lower amplitude than the initial return stroke. Each subsequent stroke usually re-uses the discharge channel taken by the previous one, but the channel may be offset from its previous position as wind displaces the hot channel.<ref>[[#Uman|Uman (1986)]] Ch. 9, p. 78.</ref>

Since recoil and dart leader processes do not occur on negative leaders, subsequent return strokes very seldom utilize the same channel on positive ground flashes which are explained later in the article.<ref name="Warner"/>