TY - JOUR
T1 - Transport of a vacuum arc plasma beam through the aperture of an annular anode
AU - Zhitomirsky, Vladimir N.
AU - Boxman, Raymond L.
AU - Goldsmith, Samuel
N1 - Funding Information:
Manuscript received December 16, 2004; revised April 21, 2005. This work was supported by the Israel Science Foundation.
PY - 2005/10
Y1 - 2005/10
N2 - The plasma beam produced by a vacuum arc plasma source was injected into a cylindrical duct through an annular anode aperture. The plasma source consisted of a frustum cone-shaped Cu cathode, and either a 20-mm-thick annular Cu anode with aperture diameter D of 10, 17, 30, 40, or 50 mm, or 35 nun thick and D = 40 or 50 mm. Magnetic coils positioned coaxially with the duct axis produced an approximately axial magnetic field guiding the plasma in the duct. The arc current, Iarc, was in the range of 30-100 A. A 130-mm-diameter negatively biased planar disk probe, positioned normal to the duct axis at a distance of 150 mm from the anode exit, was used to measure ion saturation current Ip· Ip, as well as the ion saturation current to the duct wall Id, the arc voltage Varc, and the probe and duct floating potentials with respect to the anode φp and φd, were measured as functions of D, Iarc, and the axial magnetic field B. Generally, Ip and Id increased with D and Iarc. For D = 10 mm, Ip was ∼ 0.4% of Iarc, while with D = 50 mm, Ip reached ∼ 9.5% of Iarc. However, with large D, the probability of the arc extinguishing increased. Both φp and φd were negative relative to the anode. φp became increasingly negative with increasing D, and approximately linearly depended on D. With a small D, Ip and Id increased almost linearly with B, while φd was almost independent of B. However, for a large D, Ip and Id were only slightly affected by B, and φd became less negative with increasing B.
AB - The plasma beam produced by a vacuum arc plasma source was injected into a cylindrical duct through an annular anode aperture. The plasma source consisted of a frustum cone-shaped Cu cathode, and either a 20-mm-thick annular Cu anode with aperture diameter D of 10, 17, 30, 40, or 50 mm, or 35 nun thick and D = 40 or 50 mm. Magnetic coils positioned coaxially with the duct axis produced an approximately axial magnetic field guiding the plasma in the duct. The arc current, Iarc, was in the range of 30-100 A. A 130-mm-diameter negatively biased planar disk probe, positioned normal to the duct axis at a distance of 150 mm from the anode exit, was used to measure ion saturation current Ip· Ip, as well as the ion saturation current to the duct wall Id, the arc voltage Varc, and the probe and duct floating potentials with respect to the anode φp and φd, were measured as functions of D, Iarc, and the axial magnetic field B. Generally, Ip and Id increased with D and Iarc. For D = 10 mm, Ip was ∼ 0.4% of Iarc, while with D = 50 mm, Ip reached ∼ 9.5% of Iarc. However, with large D, the probability of the arc extinguishing increased. Both φp and φd were negative relative to the anode. φp became increasingly negative with increasing D, and approximately linearly depended on D. With a small D, Ip and Id increased almost linearly with B, while φd was almost independent of B. However, for a large D, Ip and Id were only slightly affected by B, and φd became less negative with increasing B.
KW - Magnetic fields
KW - Plasma measurements
KW - Vacuum arcs
KW - Vacuum-arc plasma jet
UR - http://www.scopus.com/inward/record.url?scp=27644499240&partnerID=8YFLogxK
U2 - 10.1109/TPS.2005.856491
DO - 10.1109/TPS.2005.856491
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AN - SCOPUS:27644499240
SN - 0093-3813
VL - 33
SP - 1631
EP - 1635
JO - IEEE Transactions on Plasma Science
JF - IEEE Transactions on Plasma Science
IS - 5 I
ER -