In inductively coupled plasma spectroscopy, the use of an induction coil assembly comprising at least two helical coils which are arranged in overlapping relationship. In one practical form, the overlap is achieved by interlacing of the coils so that at least one turn of one coil is interposed between two adjacent turns of the other coil. For that purpose, the two coils will ideally be of the same diameter and will be coaxial. A tubular part of a plasma torch is contained within the space surrounded by the coil assembly, and a RF energy source is connected to an end of each coil. The other ends of the coils may be connected to ground.