Influence of Working Pressure on Ion Sensitive Probe Measurement in Microwave ECR Plasmas

In order to precisely measure the ion parameters in a microwave electron cyclotron resonance plasma using an ion sensitive probe, the dependences of the current-voltage (I-V) characteristics on the shielding height (h) and the potential difference between inner and outer electrodes (VB) have been investigated at different working pressures of 0.03 Pa and 0.8 Pa. Results show that the I-V curves at higher pressure are more sensitive to the variation of h than those at lower pressure. The influence of VB on ion temperature (Ti) measurement becomes more prominent when the pressure is increased from 0.03 Pa to 0.8 Pa. Under both pressures, the optimized h is obtained at the condition where the current reaches zero in the positive voltage region with a suitable VB of −1.5 V because of effective shielding of the electron E×B drift.

[1]  Hong-wei Cao,et al.  Measurement of Ion Parameters by Ion Sensitive Probe in ECR Plasma , 2011 .

[2]  A. Tsushima,et al.  Ion Temperature Measurement Using Ion-Sensitive Probe , 2005 .

[3]  Z. Kiss’ovski,et al.  Ion sensitive probe measurement in the linear plasma device PSI-2 , 2005 .

[4]  R. Schrittwieser,et al.  Measurements of the Parallel and Perpendicular Ion Temperatures by Means of an Ion‐sensitive Segmented Tunnel Probe , 2004 .

[5]  G. Oost,et al.  Tunnel probes for measurements of the electron and ion temperature in fusion plasmas , 2004 .

[6]  Y. Tatematsu,et al.  Ion measurement of the edge plasma in the GAMMA10 tandem mirror device with an ion sensitive probe , 2004 .

[7]  S. Masuzaki,et al.  Ion temperature measurement using an ion sensitive probe in the LHD divertor plasma , 2003 .

[8]  W. Tao,et al.  Measurement of Spatial Distributions of Electron Density and Electron Temperature in Direct Current Glow Discharge by Double Langmuir Probes , 2002 .

[9]  N. Ezumi PIC Simulation of the Motion of Plasma around Ion Sensitive Probes , 2001 .

[10]  W. Manheimer,et al.  Ion distribution functions in an Ar-Cl ECR discharge , 2000 .

[11]  I. Katsumata A Review of Ion Sensitive Probes , 1996 .

[12]  I. C. Nascimento,et al.  Simultaneous measurement of ion and electron temperatures in the scrape-off layer of a small tokamak , 1991 .

[13]  A. Hershcovitch,et al.  Electrostatic ion probe for tokamak-plasma-edge diagnostic , 1986 .

[14]  G. Matthews A combined retarding field analyser and E×B probe for measurement of ion and electron energy distribution in tokamak edge plasmas , 1984 .

[15]  J. R. Roth Ion heating and containment in an Electric Field Bumpy Torus (EFBT) plasma , 1983 .