Radial profiles of magnetic fields in the electrostatic (E) and electromagnetic (H) modes of low-frequency (similar to500 kHz) inductively coupled plasmas have been measured using miniature magnetic probes. In the low-power (similar to170 W) E-mode, the magnetic field pattern is purely linear, with the fundamental frequency harmonics only. After transition to higher-power (similar to1130 W) H-mode, the second-harmonic nonlinear azimuthal magnetic field B-phi(2omega) that is in 4-6 times larger than the fundamental frequency component B-phi(omega), has been observed. A simplified plasma fluid model explaining the generation of the second harmonics of the azimuthal magnetic field in the plasma source is proposed. The nonlinear second harmonic poloidal (r-z) rf current generating the azimuthal magnetic field B-phi(2omega) is attributed to nonlinear interactions between the fundamental frequency radial and axial magnetic fields with the azimuthal rf current. (C) 2003 American Institute of Physics.
Ostrikov, K. N., Tsakadze, E. L., Xu, S., Vladimirov, S. V., & Storer, R. G. (2003). Nonlinear electromagnetic fields in 0.5 MHz inductively coupled plasmas. Physics of Plasmas, 10(4), 1146-1151. https://doi.org/10.1063/1.1557871