Fig. 4: Measurements with VHF interferometer.
From: Laser-guided lightning
a,b, Two-dimensional maps of the VHF sources emitted during the lightning event L1 with the laser on (a) and event N6 without the laser (b). The telecommunication tower is in black whereas the laser path is in red (continuous red line when the laser is present, and dashed red line when the laser is off). Each point corresponds to a VHF emission. The colour scale bars displayed on the right correspond to the timescale. The violet section shows the region in which laser filamentation is expected.
