A cusp field or and end block can greatly increase the density G. Chevalier and F.F. Chen, Experimental modeling of inductive discharges, J. Vac. Sci. Technol. A 11, 1165 (1993)
Radial mode structure is m = +1, even when antenna is made to excite m = –1 M. Light and F.F. Chen, Helicon Wave Excitation with Helical Antennas, Phys. Plasmas 2, 1084 (1995) RH antenna LH antenna
Axial beating of radial modes M. Light, I.D. Sudit, F.F. Chen, and D. Arnush, Axial Propagation of Helicon Waves, Phys. Plasmas 2, 4094 (1995)
Density is peaked 50 cm downstream, due to pressure balance I.D. Sudit and F.F. Chen, Discharge equilibrium of a helicon plasma, Plasma Sources Sci. Technol. 5, 43 (1996)
Helical antennas are directional; Nagoya IIIs are not F.F. Chen, I.D. Sudit, and M. Light, Downstream physics of the helicon discharge, Plasma Sources Sci. Technol. 5, 173 (1996) Helical antennas are directional; Nagoya IIIs are not Beating length and KTe decay agree with theory
Rotating the field with a bifilar antenna is better than spatial rotation with helical antennas D.G. Miljak and F.F. Chen, Helicon wave excitation with rotating antenna fields, Plasma Sources Sci. Technol. 7, 61 (1998)
Injecting from both ends does not increase the density because of neutral depletion D.G. Miljak and F.F. Chen, Density limit in helicon discharges, Plasma Sources Sci. Technol. 7, 537 (1998)
Half wavelength helical antennas are better than full wavelength antennas L. Porte, S.M. Yun, F.F. Chen, and D. Arnush, Superiority of half-wavelength helicon antennas, LTP-110 (Oct. 2001)