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Improvement of Field Accuracy and Plasma Performance in the RT-1 Device

Yoshihisa YANO, Zensho YOSHIDA, Junji MORIKAWA, Haruhiko SAITOH, Hiroyuki HAYASHI and Tatsunori MIZUSHIMA

Department of Advanced Energy, University of Tokyo, Kashiwa, Chiba 277-8561, Japan

(Received 19 June 2009 / Accepted 3 July 2009 / Published 12 August 2009)

Abstract

To improve the accuracy of the magnetic field of Ring Trap-1 (RT-1), we have constructed a system of correction coils to cancel the geomagnetic field and control the attitude of the floating magnet. Without the geomagnetic field canccellation, the floating magnet tilts about 1.4 degrees. The previous prototype correction coils have been replaced by new coils that are much larger and farther from the chamber, so the error field due to the multipole components of the correction field is reduced by a factor of 30 (from 2.6% to 0.1% of the confinement field near the edge region). A significant improvement in plasma confinement has been observed (the stored energy of the plasma has been increased by a factor of 1.5).

Copyright (c) 2009 The Japan Society of Plasma Science and Nuclear Fusion Research

Keywords

levitated dipole confinement, field accuracy, geomagnetic, correction coils, high-beta plasma

DOI: 10.1585/pfr.4.039

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References

• [1] Z. Yoshida et al., Plasma Fusion Res. 1, 008 (2006).
• [2] Y. Ogawa et al., Plasma Fusion Res. 4, 020 (2009).
• [3] Kakioka magnetic observatory Japan meteorological agency website, http://www.kakioka-jma.go.jp/en/index.html
• [4] Z. Yoshida et al., High-Beta (Hot Electron) Plasma in Ring Trap 1 (RT-1), 22th IAEA Fusion Energy Conference, Switzerland, 2008, EX/P5-28.

This paper may be cited as follows:

Yoshihisa YANO, Zensho YOSHIDA, Junji MORIKAWA, Haruhiko SAITOH, Hiroyuki HAYASHI and Tatsunori MIZUSHIMA, Plasma Fusion Res. 4, 039 (2009).