24aE09P
The intrinsic plasma rotation measurement
and spectroscopic model analysis on QUEST
Yushi Maeda1, Hiroshi Idei2,Kishore Mishore1,Takumi Onchi2, Taichi Shikama3 et al.
IGSES, Kyushu Univ.1, RIAM, Kyushu Univ.2, Kyoto Univ.3

2. Experimental apparatus and spectroscopy
A slab plasma is generated near the electron
cyclotron resonance (ECR) layer by ECR waves(fRF= 8.2 GHz, Prf ~60 kW, Btor=0.29 T). The
poloidal field Bpol(<50 G) is applied to generaterotation. Since Bpol is positive, the expected current
flows in the clockwise direction viewing from thetop.
The line spectrum of the impurity ions CIII
(464.74 nm) is measured with a spectrometer. The
fiber array (25 line of sights) views plasmatangentially at a tangent radius Rtan and is connectedto the entrance slit [3]. The CCD is located at theexit slit. The profile of toroidal rotation〈Vtor(Rtan)〉
is obtained for |Rtan| < 1.1m.
3. Model analysis [4]A local Gaussian spectrumr)) at the radius r isgiven by the following formulation (1),    p (r ) 2 
 (r )
 , (1) ( , r ) exp 222  (r ) 2  (r )here    Vth0 c , Vth  Ti M i , p  0 1  Vtor c ,c : the speed of light, 0 : the center wavelength, andMi : the ion mass. The local radiation emissivity, ion
velocity and ion temperature are denoted by , Vtorand Ti, respectively. The line of sight wavelength
spectrum Ical(Rtan) is obtained by the integration ofr) along the line of sight representing by Rtan,described by Eq.(2),I cal ( , Rtan )   ( , r )dr . (2)R tan

Finally, by Gauss fitting of Ical(Rtan) line of sightprofiles of〈Icalpeak(Rtan),〈Vtor(Rtan)〉and〈Ti(Rtan)〉are determined. By comparing them with observed
ones the local profiles of r, Vtor(r) and Ti(r) areachieved.
4. Comparison of observations with the model
The Bpol dependence of〈Vtor(Rtan)〉was examined for0≦Bpol ≦50 G. When Bpol =0 G, there was norotation. Figure 1 shows the results (▲: Bpol=10 G,●: Bpol=48 G). Model calculations are indicated bydashed-lines.〈Vtor(Rtan)〉< 0 corresponds to theco-current rotation. Here ▲ and ● indicate thecounter-current rotation and co-current ones. The
latter was characterized by steep gradient at Rtan ~0.6 m. Figure 2 shows the local profile. △ isexplained by parabolic distribution (V0=0.8 km/s)
and ○ is explained by the bi-directional flow pattern(Vtor(r)=V0tanh(r-R0)+Voffset, V0=4 km/s, Voffset = -2km/s).
20

Vtor(km/s)

1. Introduction
Recently intrinsic plasma rotation in the co-current
direction has attracted attention in tokamak fusion
plasma with high performance [1]. The plasma
scrape-off width has been examined by modelinggrad B and curv B drifts against near-sonic flows
along the open field lines [2]. In the non-inducting
tokamak QUEST plasma, the co-current rotation
has been observed in the inboard poloidal field null(IPN) configuration on QUEST [3].
In this research, mechanisms of the intrinsic
rotation in the open magnetic field configuration isinvestigated. The uni- and bi-directional flow
patterns are suggested by the model calculation.

-2-4

Vtor_R_64
Vtor_R_58-60.4

Fig.1 Observation andcalculation results

0.6

Rmajor(m)

0.8

1.0

Fig.2 Local rotation profiles
at Bpol=10 G and 48 G

5. Summary
The intrinsic rotation under the open magnetic field
was observed and it was found that the direction ofrotation reversed by increasing Bpol from counter toco-current direction. Model calculation suggests
rotation flow is bi-directional at Bpol=48 G.
References[1]J.E.Rice et al., Nucl. Fusion 47 (2007)1618–1624[2]R.J.Goldston et al., Nucl. Fusion 52 (2012)013009[3] K. Mishra et al., Nucl. Fusion 55 (2015)083009[4]Y.Maeda, et al., 18th annual meeting of Kyushu/Okinawa /Yamaguchi Branch of the JSPF, (2014)