[Table of Contents]

Plasma and Fusion Research

Volume 10, 1403047 (2015)

Regular Articles


Nonlinear Entropy Transfer in ETG-TEM Turbulence via TEM Driven Zonal Flows
Yuuichi ASAHI, Akihiro ISHIZAWA1), Tomohiko WATANABE2), Hideo SUGAMA1), Hiroaki TSUTSUI and Shunji TSUJI-IIO
Tokyo Institute of Technology, Tokyo 152-8550, Japan
1)
National Institute for Fusion Science, Gifu 509-5292, Japan
2)
Department of Physics, Nagoya University, Nagoya 464-8602, Japan
(Received 4 November 2014 / Accepted 5 March 2015 / Published 26 May 2015)

Abstract

Nonlinear interplay of the electron temperature gradient (ETG) modes and the trapped electron modes (TEMs) was investigated by means of gyrokientic simulation. Focusing on the situation where both TEMs and ETG modes are linearly unstable, the effects of TEM-driven zonal flows on ETG turbulence were examined by means of entropy transfer analysis. In a statistically steady turbulence where the TEM driven zonal flows are dominant, it turned out that the zonal flows meditate the entropy transfer of the ETG modes from the low to high radial wavenumber regions. The successive entropy transfer broadens the potential fluctuation spectrum in the radial wavenumber direction. In contrast, in the situation where ETG modes are unstable but TEMs are stable, the pure ETG turbulence does not produce strong zonal flows, leading to a rather narrow spectrum in the radial wavenumber space and a higher transport level.


Keywords

gyrokinetic, turbulence, transport

DOI: 10.1585/pfr.10.1403047


References

  • [1] W. Horton, Rev. Mod. Phys. 71, 735 (1999).
  • [2] W.M. Tang, Nucl. Fusion 18, 1089 (1978).
  • [3] W. Dorland, F. Jenko, M. Kotschenreuther and B.N. Rogers, Phys. Rev. Lett. 85, 5579 (2000).
  • [4] F. Jenko, W. Dorland, M. Kotschenreuther and B.N. Rogers, Phys. Plasmas 7, 1904 (2000).
  • [5] X. Garbet, Y. Idomura, L. Villard and T.-H. Watanabe, Nucl. Fusion 50, 043002 (2010).
  • [6] T.L. Rhodes, C. Holland, S.P. Smith, A.E. White, K.H. Burrell, J. Candy, J.C. DeBoo, E.J. Doyle, J.C. Hillesheim, J.E. Kinsey, G.R. McKee, D. Mikkelsen, W.A. Peebles, C.C. Petty, R. Prater, S. Parker, Y. Chen, L. Schmitz, G.M. Staebler, R.E. Waltz, G. Wang, Z. Yan and L. Zeng, Nucl. Fusion 51, 063022 (2011).
  • [7] M. Nunami, T.-H. Watanabe, H. Sugama and K. Tanaka, Phys. Plasmas 19, 042504 (2012).
  • [8] P.H. Diamond, S.-I. Itoh, K. Itoh and T.S. Hahm, Plasma Phys. Control. Fusion 47, R35 (2005).
  • [9] B.W. Stallard, C.M. Greenfield, G.M. Staebler, C.L. Rettig, M.S. Chu, M.E. Austin, D.R. Baker, L.R. Bayor, K.H. Burrell, J.C. DeBoo, J.S. DeGrassie, E.J. Doyle, J. Lohr, G.R. McKee, R.L. Miller, W.A. Peebles, C.C. Petty, R.I. Pinsker, B.W. Rice, T.L. Rhodes, R.E. Waltz, L. Zeng and the DIII-D Team, Phys. Plasmas 6, 1978 (1999).
  • [10] Y. Asahi, A. Ishizawa, T.-H. Watanabe, H. Tsutsui and S. Tsuji-Iio, Phys. Plasmas 21, 052306 (2014).
  • [11] M. Nakata, T.-H. Watanabe and H. Sugama, Phys. Plasmas 19, 022303 (2012).
  • [12] T.-H. Watanabe, H. Sugama, M. Nunami, K. Tanaka and M. Nakata, Plasma Phys. Control. Fusion 55, 014017 (2013).
  • [13] A. Ishizawa, T.-H. Watanabe, H. Sugama, S. Maeyama and N. Nakajima, Phys. Plasmas 21, 055905 (2014).
  • [14] A. Ishizawa, S. Maeyama, T.-H. Watanabe and H. Sugama, Nucl. Fusion 53, 053007 (2013).
  • [15] T.-H. Watanabe and H. Sugama, Nucl. Fusion 46, 24 (2006).
  • [16] H. Sugama, T.-H. Watanabe and M. Nunami, Phys. Plasmas 16, 112503 (2009).
  • [17] Y. Xiao and P.J. Catto, Phys. Plasmas 13, 102311 (2006).
  • [18] L. Wang and T.S. Hahm, Phys. Plasma 16, 062309 (2009).
  • [19] F. Jenko and A. Kendl, Phys. Plasmas 9, 4103 (2002).

This paper may be cited as follows:

Yuuichi ASAHI, Akihiro ISHIZAWA, Tomohiko WATANABE, Hideo SUGAMA, Hiroaki TSUTSUI and Shunji TSUJI-IIO, Plasma Fusion Res. 10, 1403047 (2015).