Catch discharge

Schematic animation of a pre-discharge (red) with counter-growing catch discharges (blue) from the ground. The colors are meant to express the difference in charge and are not real.

A trapping discharge is an electrostatic discharge in the first phase of a lightning strike , which grows from the ground towards the previous discharge.

Before the main lightning perceived by humans appears in the case of a lightning bolt, one or more mostly negatively charged pre-discharges develop from the cloud. They build up the lightning channel through which the main lightning occurs later. Fractions of a second before these pre-discharges reach the ground , one or more very dark, bluish, positively charged catch discharges usually grow from pointed, raised objects that are electrically conductively connected to the ground, such as lightning rods on tower peaks; this is a form of corona discharge , the pre-discharges opposite. The cause is the high electric field strength in the air above the conductive tip and the tip discharge that begins there .

The emergence of the interception discharge is decisive for the point in which the lightning strikes later and is used technically in the form of interception devices .

When the pre-discharge and the capture discharge reach each other, a closed ionized lightning channel has been created. From then on, the catch discharge moves towards the cloud at around 100,000 km / s into the lightning channel and the main discharge towards the earth is induced, which is perceived as an actual bright lightning bolt.

Web links

Commons : Blitz  album with pictures, videos and audio files

• Lightning issues and lightning protection ( LEIFI )

Individual evidence

1. ↑ VDE Lightning Protection + Lightning Research - Formation of thunderstorms and lightning discharges , accessed on March 25, 2019