Phoebe Sarah Hertha Ayrton was a British engineer, mathematician, physicist and inventor, and suffragette. Known in adult life as Hertha Ayrton, born Phoebe Sarah Marks, she was awarded the Hughes Medal by the Royal Society for her work on electric arcs and ripple marks in sand and water.

The Hughes Medal is awarded by the Royal Society of London "in recognition of an original discovery in the physical sciences, particularly electricity and magnetism or their applications". Named after David E. Hughes, the medal is awarded with a gift of £1000. The medal was first awarded in 1902 to J. J. Thomson "for his numerous contributions to electric science, especially in reference to the phenomena of electric discharge in gases", and has since been awarded over one-hundred times. Unlike other Royal Society medals, the Hughes Medal has never been awarded to the same individual more than once.