Helicoidal Coil Electromagnetic Field Axis Position in Inductively Coupled Plasma Torch.

Electromagnetic field axis in a helicoidal coil is shown to be turned and displaced as related to the coil geometrical axis. Rotation angle is strongly dependent on current closure path. In an open coil, axes of electric and magnetic fields do not correspond. Explicit formulas for axes positions were obtained, well correlating with numerical results.