We report measurements of the x‐ray emission from rocket‐triggered lightning, made during the summer of 2003, using four instruments placed between 15 and 40 m from the lightning channels. X‐rays were measured 0–80 μs just prior to and at the beginning of 73% of the 26 return strokes observed. The emission was composed of multiple, very brief bursts of x‐rays in the 30–250 keV range, with each burst typically lasting less than 1 μs. The x‐rays were primarily observed to be spatially and temporally associated with the dart leaders with a possible contribution from the beginning of the return strokes, with the most intense x‐ray bursts coming from the part of the lightning channel within ∼50 m of the ground. Because triggered lightning strokes are similar to subsequent strokes in natural lightning, it is likely that x‐ray emission is a common property of natural lightning.
