Analysis of plasma equilibrium based on orbit-driven current density profile in steady-state plasma on QUEST

K. Nakamura, M. M. Alam, Y. Z. Jiang, O. Mitarai, K. Kurihara, Y. Kawamata, M. Sueoka, M. Takechi, M. Hasegawa, K. Tokunaga, K. Araki, H. Zushi, K. Hanada, A. Fujisawa, H. Idei, Y. Nagashima, S. Kawasaki, H. Nakashima, A. Higashijima, T. NagataA. Fukuyama

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Abstract

In the present RF-driven (ECCD) steady-state plasma on QUEST (Bt = 0.25 T, R = 0.68 m, a = 0.40 m), plasma current seems to flow in the open magnetic surface outside of the closed magnetic surface in the low-field region according to plasma current fitting (PCF) method. We consider that the current in the open magnetic surface is due to orbit-driven current by high-energy particles in RF-driven plasma. So based on the analysis of current density profile based on the orbit-driven current, plasma equilibrium is to be calculated. We calculated high energy particles guiding center orbits as a contour plot of conserved variable in Hamiltonian formulation and considered particles initial position with different levels of energy and pitch angles that satisfy resonance condition. Then the profile of orbit-driven current is estimated by multiplying the particle density on the resonance surface and the velocity on the orbits. This analysis shows negative current near the magnetic axis and hollow current profile is expected even if pressure driven current is considered. Considering the hollow current profile shifted toward the low-field region, the equilibrium is fitted by J-EFIT coded by MATLAB.

Original languageEnglish
Pages (from-to)1528-1533
Number of pages6
JournalFusion Engineering and Design
Volume109-111
DOIs
Publication statusPublished - Jan 1 2016

All Science Journal Classification (ASJC) codes

  • Civil and Structural Engineering
  • Nuclear Energy and Engineering
  • Materials Science(all)
  • Mechanical Engineering

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    Nakamura, K., Alam, M. M., Jiang, Y. Z., Mitarai, O., Kurihara, K., Kawamata, Y., Sueoka, M., Takechi, M., Hasegawa, M., Tokunaga, K., Araki, K., Zushi, H., Hanada, K., Fujisawa, A., Idei, H., Nagashima, Y., Kawasaki, S., Nakashima, H., Higashijima, A., ... Fukuyama, A. (2016). Analysis of plasma equilibrium based on orbit-driven current density profile in steady-state plasma on QUEST. Fusion Engineering and Design, 109-111, 1528-1533. https://doi.org/10.1016/j.fusengdes.2015.11.035