X-ray topographic observations of edge dislocation glide on non- basal planes in ice

White synchrotron X-radiation topography has been used to observe the motion of dislocations in single crystals of ice under a compressive stress in the [11̄00] direction, for which there is no resolved stress on the basal plane. Dislocations with [12̄10] and [2̄110] Burgers vectors were nucleated from surface scratches, and their edge components were observed to glide on non-basal planes, which may be prismatic or may have unspecific pyramidal character. Screw components are not mobile on such planes. -Authors