Arcs in the G-Ring

Original NASA caption:"This sequence of images shows a faint arc of material in Saturn's G-Ring, a tenuous ring outside the main Ring System. These images were each taken about 45' apart. During this time, the arc (slightly brighter than the Ring itself) moves around the outer edge of the Ring. The arc is visible on the lower part of the Ring in the first image, just beneath the ansa (or outer edge). In the second image the arc is easily seen on the outer edge and then faintly just above the outer edge in the third image.
What makes this part of the G-Ring brighter than other parts is not clear. However, the existence of this arc might hold clues about how this ring was formed and where the material which makes up this ring comes from. These 3 images were taken in polarized near-infrared light using the Cassini spacecraft narrow-angle camera on May 24, 2005, at a distance of approx. 1,7 MKM (about 1,1 MMs) from Saturn. Resolution in the original images was about 97 Km per pixel".