Particle Orbit Analysis in the Finite Beta Plasma of the Large Helical Device using Real Coordinates
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Abstract
Highenergy particles in a finite beta plasma of the Large Helical Device (LHD) are numerically traced in a real coordinate system. We investigate particle orbits by changing the beta value and/or the magnetic field strength. No significant difference is found in the particle orbit classifications between the vacuum magnetic field and the finite beta plasma cases. The deviation of a banana orbit from the flux surfaces strongly depends on the beta value, although the deviation of the orbit of a passing particle is independent of the beta value. In addition, the deviation of the orbit of the passing particle, rather than that of the bananaorbit particles, depends on the magnetic field strength. We also examine the effect of reentering particles, which repeatedly pass in and out of the last closed flux surface, in the finite beta plasma of the LHD. It is found that the number of reentering particles in the finite beta plasma is larger than that in the vacuum magnetic field. As a result, the role of reentering particles in the finite beta plasma of the LHD is more important than that in the vacuum magnetic field, and the effect of the chargeexchange reaction on particle confinement in the finite beta plasma is large.
Journal

 Plasma and Fusion Research

Plasma and Fusion Research (3), 016016, 2008
The Japan Society of Plasma Science and Nuclear Fusion Research