The transport of a vacuum arc produced plasma beam along a magnetized cylindrical duct was studied experimentally. The plasma source consisted of a Sn or an Al cathode and a 17 mm i.d. annular copper anode through which the plasma beam entered into the 160 mm diameter and 500 mm length cylindrical duct. Arc current, Iarc, was in the range of 30-100 A. Three magnetic coils positioned co-axially with the duct axis produced an approximately axial guiding magnetic field, Bg ≤20 mT in the duct. A 130 mm diam. movable planar disk probe, positioned normal to the duct axis, was used to measure the ion saturation current, Iprobe, along the duct. The ion current to the duct wall, Iduct, and the probe and duct floating potentials, φprobe and φduct, respectively, were measured as functions of Bg, and the axial distance of the probe from the anode, L. Generally, Iprobe decreased while Iduct increased with L, and the sum Iprobe+Iduct was approximately independent of L. For an Al arc, Iprobe and Iduct initially increased as a function of Iarc, reached a maximum at Iarc=40-45 A, and then decreased by a factor of 2-2.5 relative to their maximal values. Both φprobe and φduct were negative relative to the grounded anode. φprobe became more negative as L or Bg were increased, while φduct depended only weakly on L.
|Number of pages||4|
|State||Published - 2002|
|Event||XXth International Symposium on Discharges and Electrical Insulation in Vacuum (ISDEIV) - Tours, France|
Duration: 1 Jul 2002 → 5 Jul 2002
|Conference||XXth International Symposium on Discharges and Electrical Insulation in Vacuum (ISDEIV)|
|Period||1/07/02 → 5/07/02|