An inductively coupled plasma source is provided with a peripheral ionization source for producing a high-density plasma in a vacuum chamber for semiconductor wafer coating or etching. The source includes a segmented configuration having high and low radiation segments and produces a generally ring-shaped array of alternating high and low energy concentrations in the plasma around the periphery of the chamber. Energy is coupled from a segmented low inductance antenna through a dielectric window or array of windows and through a segmented shield or baffle. The antenna has concentrated conductor segments through which current flows in lengths of closely-spaced windings of a single conductor to produce high magnetic fields that couple through the high-transparency shield segments into the chamber, and alternating distributed conductor segments through which current flows in lengths of more widely-spaced windings of the conductor to produce weaker magnetic fields aligned with more opaque shield sections that couple less energy to the plasma.