A slightly schematized/simplified version of one form of the ancient symbol of the Mesopotamian sun-god Shamash, with alternate pointy and wavy rays.  According to Gods, Demons, and Symbols of Ancient Mesopotamia: An Illustrated Dictionary by Jeremy Black and Anthony Green (1992, ISBN 0-292-70794-0), p. 168, it occurs "from the Akkadian down to the Neo-Babylonian period", and "The Akkadian names of the symbol were šamšatu and niphu.  It was often represented on a pole as a standard."
This vector image includes elements that have been taken or adapted from this file:
AnonMoosmodified by FOX 52