Effect of Faraday shields on capacitive coupling

1
Effect of Faraday shields on capacitive coupling
D.D. Blackwell and F.F. Chen, 2D imaging of a
helicon discharge, Plasma Sources Sci. Technol.
6, 569 (1997)
No shield
With shield
2
m 1 mode much stronger than m 1
D.D. Blackwell and F.F. Chen, 2D imaging of a
helicon discharge, Plasma Sources Sci. Technol.
6, 569 (1997)
m 1
m 1
3
Development of a time-resolved energy analyzer
D.D. Blackwell and F.F. Chen, Time-resolved
measurements of the EEDF in a helicon plasma,
Plasma Sources Sci. Technol. 10, 226 (2001)
RF modulated electron gun for calibration
2-electrode gridded analyzer with RF response
4
Time-resolved EEDFs show no fast electronsabove
a threshold of 10 -4
F.F. Chen and D.D. Blackwell, Upper limit to
Landau damping in helicon discharges, Phys. Rev.
Lett. 82, 2677 (1999)
I-V swept by oscillating Vs
I-V at two RF phases
Loading resistance agrees with calculations w/o
L.D.
Injecting a current causes a beam-plasma
instability
5
Development of an RF J-dot probe
D.D. Blackwell, T.G. Madziwa, D. Arnush, and F.F.
Chen, Evidence for Trivelpiece-Gould modes in a
helicon discharge, LTP-106 (June, 2001)
6
Evidence for Trivelpiece-Gould modes
D.D. Blackwell, T.G. Madziwa, D. Arnush, and F.F.
Chen, Evidence for Trivelpiece-Gould modes in a
helicon discharge, LTP-106 (June, 2001)
"Wings" are seen in Jz but not in Bz.
"Wings" are not predicted by theory if TG modes
are neglected.