26aA02
非平衡極限	 -	 直線磁化プラズマにおける	 ドリフト波・渦・帯状流間の新しい相互作用の観測	 
Non-Equilibrium and Extreme State –A new mutual-interaction between drift waves, eddy and zonal flow in linear
magnetized plasma	 荒川弘之1)，稲垣滋2)，佐々木真2)，小菅佑輔2), 小林達哉3), 永島芳彦2)，
山田琢磨2)，藤澤彰英2)，糟谷直宏2)，Maxime Lesur2), , 伊藤早苗2)，伊藤公孝3)
H. Arakawa1), S. Inagaki2), M. Sasaki2), Y. Kosuga2), T. Kobayashi3), Y. Nagashima2),
T. Yamada2), A. Fujisawa2), N. Kasuya2), M. Lesur2), S.-I. Itoh2) and K. Itoh3)
1) Teikyo University, 6-22 Misakimachi, Omuta 836-8505, Japan
帝京大学 〒836-8505 福岡県大牟田市岬町6-222) Kyushu University, 6-1 Kasuga-Koen, Kasuga 816-8580, Japan
九州大学〒816-8580	  春日市春日公園6-13) National Institute for Fusion Science,322-6 Oroshi-cho, Toki 509-5292, Japan
核融合科学研究所	  〒509-5292	  土岐市下石町322-6

Role of turbulence, zonal flow, mean flow on
dynamics of transport is one of the most important
issues to be clarified. Dynamic interactions between
a solitary drift wave structure and zonal
perturbations in a linear cylindrical device havebeen observed in our previous work [1]. In thisstudy, organization of a long-lived solitary eddy
and its mutual interactions with drift-wave andzonal flows in cylindrical magnetized plasma areobserved.
Turbulence excitation experiments wereperformed on the Large Mirror Device Upgrade(LMD-U). Cylindrical helicon plasma with adiameter of approximately 0.1 m and an axial
length of 3.74 m is produced by the RF wave in aquartz tube and is radially restricted by the axial
magnetic field. The operational conditions are 3 kW
RF power, 900 G magnetic field and 5 mTorr argon
gas pressure.
The azimuthal cross-section image isreconstructed by using a 64-channel azimuthalprobe array and a radially movable probe. Figure 1
shows the reconstructed two-dimensional structureof ion saturation fluctuation (δIis) and floating
potential fluctuation (δVf), where filled contours
denote δIis and contour lines denote δVf (solid lineor dotted line indicates positive or negative value).
A purple solid circle indicates the organization of asolitary (radially and azimuthally localized) eddy.
The spatiotemporal structure of the solitary
eddy is closely related to that of the zonal flow. The
solitary eddy is organized around an inner antinodeof the zonal flow. No eddy is observed in the outerantinode of the zonal flow. Note that the maximum
velocity around the solitary eddy is ~ 1 km/s and ismuch faster than zonal flow (~ 0.1 km/s). The eddy
lives during a phase where the azimuthal flow isaccelerated toward the electron diamagnetic
direction. The Reynolds stress is evaluated byfloating potential measurements. The Reynolds
stress is generated around the instantaneous radial
location of the eddy. The Reynolds force,acceleration of azimuthal flow, caused by the eddy,
is calculated from the radial gradient of Reynolds
stress. The Reynolds force indicates that theorganization of eddy accelerates electron
diamagnetic azimuthal flow.
This work is supported by the grant-in-aid for
Scientific Research of JSPS (15H02155,15H02335), by the collaboration programs ofRIAM of Kyushu University and of NIFS
(NIFS10KOAP023), and by Asada Science
Foundation.
[1] H. Arakawa et. al., Plasma Phys. Control.
Fusion 53 (2011) 115009

Fig. 1: Two-dimensional structure of the ion saturationfluctuation (filled contour) and floating potential
fluctuation (contour line). A purple solid circle

indicates the solitary eddy.