Figure 4

(A) High-speed ICCD images (a1)–(f1), APPJ length (g1) and voltage curve (h1) for the 4th positive pulse in the bunch with the first positive pulse as in Fig. 3B. (B) The 16th positive pulse in the bunch with the first negative pulse, as shown in Fig. 1B(b). The exposure for frames was 50 ns with 5 accumulations in (a1)–(f1) and 50 ns with 15 accumulations in (a2)–(f2). The labels in the frames (a)–(f) corresponds to position of points indicated in graphs (g1) and (g2). The dashed contours in (a) are the tube’s borders.