Detailed insights are gained from taking a more careful look at a series of images from the video shown in Section S8 of the SI. Here, an inhomogeneous distribution of discharges along the wire is observed, with regions of lower and higher discharge density (discharge agglomerates). A similar phenomenon was reported elsewhere for planar electrodes. From subsequent images of the discharges, we determined the velocity of individual discharges and that of discharge agglomerates (see Section S8 in the SI). The velocity distribution of individual discharges suggests a net velocity of zero in either direction (Fig. ) and, hence, can not be at the origin of the observed upward motion of the discharges. However, the mean group speed of all discharges (or discharge agglomerates) is about 0.19 m s -1 (0.22 m s -1 for the second data set) in an upward direction (see also Fig. ). To gain more definite values including error bars larger data sets are required. This means that the upward movement of discharge groups is not a combination of many upward-moving individual discharges. Rather, discharges at the lower part of the group extinguish, and new discharges ignite at the upper part of the group. The effect of the preferred ignition of discharges in the vicinity of a group of discharges was observed elsewhere on planar electrodes. A possible explanation could be that hot gas ascends, and with it potentially ions or other species which could enable easier re-ignition, similar to a gliding arc discharge, sometimes denoted as "Jacob's ladder". Next, we focus on the size and shape of the individual discharges observed in each image. An example image is given in Fig. . In comparison, Fig. shows a schematic illustration of the wire, the vapor layer, the electrolyte, and discharges with different shapes and at different locations. For the discharges, we assume a spheroid shape, which can be either oblate or prolate depending on the ratio of vapor layer thickness and the lateral diameter of the discharges. In the 2-dimensional camera images, the observed shape depends on the position of the discharge on the wire. A discharge located at the center of the wire appears circular (D1 in Fig. ). For the discharges at the edge of the wire (D2 and D3), the vertical length of the discharge image corresponds to its lateral diameter. In contrast, the horizontal length corresponds to the vapor layer thickness. The 2dimensional shape is, in both cases, an ellipse, with the major axis parallel (D1) or perpendicular (D2) to the wire surface. Thus, in the following we distinguish between the discharges For each discharge spot, an ellipse was fitted to the discharge border, as illustrated in Fig. . This yields the ellipse height h, i.e., the length of the major axis (green line), the ellipse width w, i.e., the length of the minor axis (orange line), and the angle γ between the major axis and the y-axis. The major axis is parallel to the wire for γ = 0°and perpendicular for 90°. For the following analysis, discharges smaller than two pixels were omitted.