Ion extraction from magnetically driven shunting‐arc plasma and density estimation at sheath boundary

• Osamu Kumagai

• Seiji Mukaigawa

• Koichi Takaki

• Tamiya Fujiwara

• Ken Yukimura

• Kenichi Ego

Abstract

Ion extraction from a magnetically driven shunting arc plasma and the plasma density at the sheath boundary are described in this paper. The plasma density is obtained using current and voltage waveforms for a target which is immersed in the plasma to extract the carbon ions. A 40‐mm‐long carbon rod which is 2 mm in diameter is employed as a solid‐state plasma source. A large current of more than 1 kA is supplied from a charged‐up 20‐µF capacitor to heat the carbon rod and to vaporize the rod materials. The shunting arc plasma generated along the rod surface is driven by the Lorenz force and is accelerated toward the muzzle of a plasma launcher which consists of a pair of 100‐mm‐long carbon plates. A 64‐mm‐diameter brass disk is placed 100 mm away from the carbon rod and is used as the target. A 10‐µs‐wide negative pulse bias voltage is applied to the target for the extraction of the carbon ions from the shunting arc plasma. The ion density near the sheath boundary around the target is obtained using two procedures: utilization of the stationary target current to determine the ion current and/or utilization of the target bias voltage waveforms. The ion density is obtained as 1.1×10 15 m −3 at µs after the arc ignition using the target current. The density is larger than the density of 5.1×10 14 m −3 obtained using the waveform of the target voltage. The plasma density is also predicted using a Bohm equation and a momentum conservation equation. The plasma density is 1.6×10 15 m −3 at 100 µs after the arc ignition. The density decreases as the time from arc ignition increases. © 2007 Wiley Periodicals, Inc. Electr Eng Jpn, 162(2): 1– 9, 2008; Published online in Wiley InterScience (<jats:ext-link xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="http://www.interscience.wiley.com">www.interscience.wiley.com ). DOI 10.1002/eej.20553

Journal

• Electrical Engineering in Japan

  Electrical Engineering in Japan 162 (2), 1-9, 2007-10-17

  Wiley

Keywords

• Electrical and Electronic Engineering
• Energy Engineering and Power Technology

Details

• CRID: 1361697223508659072
• NII Article ID: 210000181373
• DOI: 10.1002/eej.20553
• ISSN: 15206416
• ISSN: 04247760
• Web Site: https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1002%2Feej.20553
• Web Site: https://onlinelibrary.wiley.com/doi/pdf/10.1002/eej.20553
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