So I googled it to find out more.
Can see the pictures at NY Times article
(images too large to insert here)
What caught my attention was ...
Pan is one of Saturn’s shepherd moons, clearing out a 200-mile-wide space in Saturn’s rings known as the Encke Gap.
Still, it didn't click with me until, right at the end of the article, they mentioned ...
In January, during a flyby of Daphnis, another of the shepherd moons, Cassini was able to successfully take only one photograph.
And I read the caption with the picture.
Cassini took this image of Daphnis, a 5-mile-wide moon, in January. Daphnis’ gravity also opened a gap in Saturn’s rings and created the scalloped wave pattern at the ring edges. Credit NASA/JPL-Caltech/Space Science Institute
On reading that I thought, what? "gravity opened a gap in the rings".
Gravity is a force of attraction. Isn't it?
I think it must be Daphnis' (and Pan's) electric field that clears the dust in it's orbital path, by repelling it.