Proceedings of ITC/ISHW2007

Particle transport and fluctuation characteristics aroundneoclassically optimized configurations in LHD
K. Tanaka, C. Michael, aL. N. Vyacheslavov, M. Yokoyama, bS. Murakami, cA. Wakasa, dH. Takenaga,eK. Muraoka, K. Kawahata, T. Tokuzawa, T. Akiyama, K. Ida, M. Yoshinuma, I. Yamada, K.
Narihara, H. Yamada and the LHD Experimental group
National Institute for Fusion Science,322-6 Oroshi-cho, Toki 509-5292, Japana
Budker Institute of Nuclear Physics, 630090 Nobosibirsk, Russiab
Department of Nuclear Engineering, Kyoto Univ., Kyoto 606-8501, Japanc
Graduate School of Engineering, Hokkaido Univ., Sapporo 060-8628, Japand
Japan Atomic Energy Agency, 801-1, Mukoyama, Naka 311-0193, Japane
School of Engineering, Chubu Univ., Kasugai 487-8501, Japan
Density profiles in LHD were measured and particle transport coefficients were estimated from density
modulation experiments in LHD. The data set contains the wide region of discharge condition. The dataset ofdifferent magnetic axis, toroidal magnetic filed and heating power provided data set of widely scanned neoclassicaltransport. At minimized neoclassical transport configuration in the dataset (Rax=3.5m, Bt=2.8T) showed peaked
density profile. Its peaking factor increased gradually with decrease of collisional frequency. This is a similar result
observed in tokamak data base. At other configuration, peaking factor reduced with decrease of collsional frequency.
Data set showed that larger contribution of neoclassical transport produced hollowed density profile. Comparison
between neoclassical and experimental estimated particle diffusivity showed different minimum condition. Thissuggests neoclassical optimization is not same as anomalous optimization. Clear difference of spatial profile ofturbulence was observed between hollowed and peaked density profiles. Major part of fluctuation existed in theunstable region of linear growth rate of ion temperature gradient mode.
Keywords: density profile, peaking factor, density modulation experiments, neoclassical transport,
anomalous transport, diffusion coefficient, convection velocity, phase contrast imaging, turbulence

1. Introduction
Optimization of magnetic configuration for reducing
energy and particle transports is an important issue forstudies in stellarator/heliotron devices. In LHD, magnetic
properties can be changed by scanning magnetic axis
positions then systematic studies of the effects ofmagnetic configuration on transports are possible.
Optimized configuration for reducing neoclassicaltransport was studied for Rax=3.5~3.75m using the
DCOM code and was found that the neoclassicaltransport was to be minimum at Rax=3.5m in the plateau
regime and at Rax=3.53m in the 1/ν regime [1]. Then, it
was experimentally observed that the effective helicalripple, which is an influential parameter of neoclassicaltransport in the 1/ν regime, played an important role on
global energy confinement [2]. Inter machine studies
show smaller effective helical ripple configuration
showed higher enhancement of global energy
author’s e-mail: ktanakal@nifs.ac.jp

confinements compared with international stellarator
scaling 2005 [2]. This suggests that neoclassicaloptimization may also affect anomalous transport because
transport in the data set of [2] was dominated byanomalous transport. In the previous work, systematicstudies of particle transport and fluctuation properties
were carried out at Rax=3.6~3.9 m [3,4]. Particle diffusion
was found to be anomalous and the smaller at the more
inward shifted configuration. Simultaneously, the smallerfluctuation level was observed. Density profiles werehollow in many case of discharge, and became peaked
ones at higher magnetic fields at higher collisionality.
When density profiles were hollow, particle convection
was comparable with that from the neoclassicalprediction.
In this article, particle transports were studied ataround optimized neoclassical configuration in order toinvestigate linkage between neoclassical and anomalousProceedings of ITC/ISHW2007
plateau and banana region can be defined [9]. LHD is

0

0.5
ρ

1

(d)

(e)

1

-3

2

19

2

19

-3

n (x10 m )

1

e

1

1

e

e

1
0

T (eV)

19

2

(c)

2

0

0

0.5
ρ

1

0
0

0.5
ρ

1

0
0

Rax=3.75m, Bt=2.64m
2
(f)

3

e

(b)

2

Rax=3.50m, Bt=2.83T

Bt=2.75T

T (keV)1MW-3n (x10 m )(a)e

T (keV)

3

2.7MW

0.5ρ

1

1

e

Rax=3.6m
Bt=1.49T

Rax=3.6m, Bt=2.75,2.8T
8.5MW

n (x10 m )transport.

0
0

0
0.5

ρ

1

0

0.5
ρ

1

Fig.1 Comparison of (a), (c), (e) Te and (b), (d), (f) ne profiles under different condition. (a), (b) different NBI power,(c), (d) different magnetic field (e), (f) different magnetic configuration (Rax=3.5m and 3.75m is reduced and enhanced
helical ripple configuration respectively

2. Experimental results
2.1 General character of density profile in LHD
Figure 1 shows electron temperature (Te) and electron
density (ne) profiles under various conditions. The density
profiles were measured by multi channel far-infraredinterferometer [5] and electron temperature profiles were
measured by YAG Thomson scattering [6]. The density
profiles vary depending o the discharge condition. This isclear contrast to tokamak density profiles, which are
peaked in the most of the case [7, 8]. Density profilechanges from peaked one to hollow one with increasing ofheating power as shown in Fig. 1 (b). With higher heating
power, steeper Te gradient was formed. This higher Te
gradient can cause outward convective flux [3]. Figure 1(c) and (d) show Te and ne profiles under different toroidal
magnetic field (Bt) with almost identical Te profiles. The
toroidal magnetic field is also can affects the density
profile. The density profiles became more hollow at lower
magnetic field. The magnetic configuration can affectdensity profile as well. As shown in Fig.1 (f), at more
outward configuration, density profiles tend to be hollow.
Magnetic axis position were also influential parameter on
density porofile.
Figure 2 shows parameter dependence of density
peaking factor. The density peaking factor was defined as
the ratio between the density at ρ (normalized radius) =0.2
and volume averaged density. The volume averaged
density was calculated within the last closed flux surface.
Figure 2 (a) shows comparison of dependence on νb*,which is normalized by the collisional frequency at plateau
and banana regime and defined by the following equation.

ν*b=νei/(εt3/2vT/qR)(1)

where εt is an inverse aspect ratio, vT is an electron
thermal velocity, q is a safety factor and R is a major
radius. In the single helicity stellarator, the boundary ofmultiple helicity configuration, however, for thecomparison with JT60U elmy H mode data, νb* was used.
In JT60U, the peaking factor increases with decrease of νb*.
This is widely observed in tokamak [7,8]. In LHD, density
peaking gradually increased with decrease of νb* at
Rax=3.5m, Bt=2.8T only. At other configuration(Rax=3.6m in Bt=2.75,2.8T, Rax=3.75m in Bt=2.64T and
Rax=3.9m, Bt=2.54T), the density peaking factor reducedwith decrease of νb*. This is an opposite tendency totokamak.
The data in Fig.2 are from NBI heated plasma,
however, particle fueling from the NBI did not affectdensity peaking in both JT60U and LHD [3,4,7]. The
variations of density profiles are not due to the differenceof particle fueling but due to the difference of transport.
Figure 2(a) suggests there is a common physics mechanism
to determine density profile in JT60U and Rax=3.5m,
Bt=2.8T in LHD, but there are different mechanism inother configuration of LHD.
Figure 2 (b) and (c) show dependence on normalized
collision frequency (νh*) of the stellarator/helicalconfigurations, which is defined as following equation.

ν*h = νei/(εeff3/2vT/qR)(2)

where εeff is an effective helical ripple, which represents
multiple helicity and is defined as [10],⎛ 9 2 ν ⎞2 / 3
εeff = ⎜D
2 ⎟⎝ 16 v d ⎠(3)

where ν, vd and D are the collision frequency, the drift
velocity and the particle diffusivity in the enhanced
helical ripple trapped region (the 1/ν region), respectively.
At the upper boundary of the 1/ν region, ν*h becomesaround unity.
As shown in Fig.2 (b), (c), the density peaking factor
reduced with decrease of ν*h. Also, configuration
dependence on ν*h became clear compared with Fig.2 (a).

Proceedings of ITC/ISHW2007

Rax=3.9m, Bt=2.54T
JT60U Elmy H mode Bt=2~2.1T

1
0.6

-1

10

0

10
ν∗b ρ=0.5

101

0.6 -1
10

0

1

10
10
ν∗h at ρ=0.5

2

10

0.6 -1
10

e

e

1

1.2
1
0.8

0.8

0.8

0.8

1.2

1.4

e

1

n (0.2)/(n >

e

1.2

e

e

ne(0.2)/<ne>n (0.2)/(n >en (0.2)/(n >

1.2

(e)

1.4

1.4

1.4

1.4

1.6

(d)

(c)

(b)

1.6

Rax=3.75m, Bt=1.5T
Rax=3.9m, Bt=1.54T

1.6

10

0

10

1

ν at ρ=0.5
*

10

2

1.2
1

e

(a)

1.8

Rax=3.53m, Bt=1.45T
Rax=3.6m, Bt=1.49T
1.6

1.6

2

n (0.2)/(n >Rax=3.5m, Bt=2.8T
Rax=3.6m, Bt=2.75,2.8T
Rax=3.75m, Bt=2.64T

0.6
3.5

0.8
0.6

3.6 3.7 3.8 3.9
Mganetic Axis (m)

4

10

-2

-1

ε

h_eff

10
at ρ=0.5h

2

D (m /sec)

2

D (m /sec)

Fig.2 Parameter dependence of density peaking factor (a) comparison between LHD and JT60U, comparison between
four configuration of LHD at (b) high filed and (c) low filed, dependence on (d) shifted magnetic axis position and (e)effective helical ripple
Data set of four configurations (Rax=3.5, 3.6, 3.75 andripple played a role on density profile as well as global
3.9m) contained different ν*h and corresponding different
energy confinement [2]. However, as shown in Fig.2 (e),peaking factor. At both high field (Fig.2 (b) ) and low field
the density peaking varies at almost same εeff. Other hidden(Fig.2 (c)), the density peaking factor was higher at moreparameter should exist to determine density profile.
inward shifted configuration, where neoclassical transport
was smaller. At the lower magnetic filed, density peaking
2.2 Parameter dependence of particle transports
factor was smaller and peaking factor depends more clearlyParticle transport in LHD was studied from density
on ν*h. As shown in Fig. 1 (d), density profile becomes
modulation experiments [3,4]. The diffusion coefficient(D) and convection velocity (V) were determined to fit
more hollow at lower field. And the hollow density profile
modulation amplitude, phase and background density
can be due to neoclassical outward convection [3]. One
profiles [3,4]. Figure 3 shows the model used for the fitting.
possible interpretation is, at lower field, the contribution of
When modulation frequency is high or diffusion coefficientneoclassical can became larger.
low, model of spatially constant D was used as shown in
Figure 2 (d) shows peaking factor dependence on
Fig.3 (a). When modulation penetrated deeper to core, two
shifted magnetic axis. The appropriate magnetic flux
diffusion coefficient model was used as shown in Fig.3 (b).
surface was selected for the Abel inversion and mapping
for Thomson scattering. The axis position is at the verticalD(ρ=0.70~1.00)
D( ρ=0.40~0.70)
edge_exp
core_exp
cross section. One important thing is the data of Fig.2 (d)D(ρ=0.70~1.00)
D(ρ=0.40~ 0.70)
edge_neo
core_neoincluded both low and high filed. The peaking factor of
Rax=3.6m, Bt=2.75,2.8T
Rax=3.5m, Bt=2.8T
shifted data of Rax=3.53m at 1.45T was close to the0core exp.
0
10 edge exp.
10 edge exp.
α=0.86peaking factor of Rax=3.75m at 2.64T. This indicates that
α=1.02
α=2.32
core exp.
-1-1
the shifted inward configuration is equivalent to the
α=1.8310
10
outward shifted configuration without Shavranov shift.
-2-2edge neo.
1010edge neo.
Figure 2 (e) shows dependence on effective helical
α=2.67
core neo.
core neo.
α=3.20α=2.47-3-3
ripple (eq.(2)). The effective helical ripple was calculated
α=2.9210
10taking into account for the finite beta effects [11]. Most of
0.2
0.4 0.60.81
30.2
0.4 0.60.8 1
3
Te(keV)the data of LHD in Fig.2 are in plateau regime, where ν*hTe(keV)is larger than unity. Although the effective helical ripple isFig. 4 Electron temperature dependence of diffusion
representative ripple in 1/ν regime, the effective helicalcoefficient (a) Rax=3.5m, Bt=2.8T and (b)Rax=3.6m ,Bt=2.75,2.8T. Dcore_exp, Dedge_exp are(a)δρ (b)
0.7 (c)Dedge
experimentally estimated core and edge diffusion
D~Dedge
Vcore
Dcore
1.0 ρ
coefficient. Dcore_neo, Dedge_neo are neoclassicalρv
0.4
0.7 1.0 V
values calculated by DCOM. Error bar of experimental
edge
ρ
ρ
ρd
values are fitting error, error bar of neoclassical values
Fig.3 Assumed profile of D and V. (a) spatiallyare standard deviations at ρ=0.4~0.7 for core value, andconstant D for localized modulation amplitude (b) two
at ρ=0.7~1-.0 for edge value. Te is also averaged atvariable D for core sensitive case and (c) two variableρ=0.4~0.7 for core value, and at ρ=0.7~1-.0 for edge
V for all cases
value.

Proceedings of ITC/ISHW2007

-0.5
-1
-1.5
0.5 0.7 1

2

3 4 5

-gradT /T (m-1)
e

e

(b)
1
0.5
0
-0.5
-1
-1.5
0.6

1

2
3 4 5 6
- gradTe (m-1)

Rax=3.6m, Bt=2.75,2.8T
1.5

V

1

neo

Rax=3.6m, Bt=2.75, 2.8T(c)Outwardexp

Outward

V

0.5
0
-0.5

Inward0

Rax=3.5m, Bt=2.8T
1.5

neo

V at ρ=0.7 (m/sec)

0.5

InwardV at ρ=0.7 (m/sec)

(a)
1

V

InwardRax=3.5m, Bt=2.8T

V at ρ=0.7 (m/sec)

exp

Outward

V
1.5

-1
-1.5
0.4 0.6 0.8 1
2
Te (keV)

3 4

Fig.5 Dependence of Vcore (at ρ=0.7) on (a) normalized Te gradient, (b) Te gradient and (c) Te.
normalized Te gradient, Te gradient and Te are averaged value at ρ =0.4~0.7.
In the model of Fig.3 (b), the diffusion coefficient transit at
ρ=ρd with transition with δρ. The convection velocity was
assumed to be zero at plasma center and to increaselinearly and change slope at ρ=ρv. The value of ρd was
fixed to be 0.7 for all cases. For Rax=3.5m, Bt=2.8T, δρ
was fixed to 0.6 and , ρv was fixed to be 0.5. For otherconfiguration, when modulation penetrated deeper to core,δρ was fixed to 0.3 and ρv was fixed to be 0.5. In order tocompare with previous results [3,4], Dedge was Dcore, Vedge
and Vcore was defined as follows. The spatial constant D
was used as a Dedge, since the modulation amplitude was
localized in the edge region. Dcore and Dedge were defined
the averaged value between ρ =0.4 and 0.7 and between ρ=0.7 and 1.0 respectively for the two values model of D.
Vcore and Vedge was defined as the value at ρ=0.7 and ρ=1.0
respectively.
Figure 4 shows the Te dependence of Dcore and Dedge.
Neoclassical values calculated by DCOM[1] are also
shown. The fitted lines are A× Teα , where A is a
proportional factor and α is an exponent. Neoclassicalvalues are smaller at Rax=3.5m than at Rax=3.6m at same
Te. However, experimental estimated Dcore and Dedge werelarger at Rax=3.5m than at 3.6m. Clear difference of Te
dependence of both neoclassical and anomalous D was
also observed. The exponent of both neoclassical andexperimental Dcore and Dedge were larger at Rax=3.5m thanat Rax=3.6m. At Rax=3.5m, the exponent of Dcore_neo werefactor 1.6 larger than at Dcore_exp and exponent of Deddge_neo
were factor 1.4 larger than Dcore_exp. At Rax=3.6m, theexponent of Dcore_neo were factor 2.6 larger than at Dcore_exp
and exponent of Deddge_neo were factor 2.6 larger thanDcore_exp. At Rax=3.6m, large difference of the exponent
between neoclassical and anomalous D were observed.
This suggests the neoclassical D will be close toexperimental D at higher Te at Rax=3.6m .
Figure 5 shows comparison of parameter dependenceof Vcore of neoclassical and experimental values. The
neoclassical particle flux is given by the following
equation [12].

⎧ ∇n eE ⎛ D 3 ⎞ ∇T ⎫
Γ e _ neo = −nD1 ⎨ e + r + ⎜⎜ 2 − ⎟⎟ e ⎬Te ⎝ D1 2 ⎠ Te ⎭
⎩ ne

(4)

The off diagonal term of the eq.(4) is convective flux, then ,neoclassical convection velocity was defined by thefollowing equation.
⎧ eE ⎛ D 3 ⎞ ∇T ⎫Ve _ neo = − D1 ⎨ r + ⎜⎜ 2 − ⎟⎟ e ⎬⎩ Te ⎝ D1 2 ⎠ Te ⎭(5)

The data set used in this article was in the transition region
or ion root region. In equation (4), the contribution ofradial electric field on convection velocity was small andneoclassical convection was dominated by thermo
diffusion term, which is the second term of eq.(5). As
shown in Fig. 5, at Rax=3.6m, when convection velocity
was outward directed and density profile was hollow,
experimental convection velocity was comparable withneoclassical convection. This is same as the case of
Rax=3.75, and 3.9m [3]. The clear Te dependence of Vcore
was observed as shown in Fig.5 (c). So, the electron
temperature is likely to be determine Vcore as well as D

2.3 Configuration dependence of neoclassical andanomalous particle transport coefficient
There is an expectation that neoclassical optimization
minimize anomalous transport simultaneously [2]. This is
supported by theoretical work. In the single helicity
heliotron configuration, smaller helical ripple configuration
can generate larger zonal flow and can stabilize turbulence
effectively [13]. The configuration dependence of particle
transport coefficients are shown in Fig. (6) about high field
case, and in Fig.7 about low field case.
Since both diffusion coefficients and convection
velocity depends on Te as described in the previous section,
for the comparisons between different configurations, thevalues at the same Te were connected. As shown in Fig. 6(a) and (b), at high field, the minimum of neoclassical D is

Experiment
Neoclassical1
10
Lines at Te core=1.25keV(a)

1

10

0

10
10

-1

10

-2

10

-3

Lines at T

1.5

=0.65keV(b)

eedge

0

10

V at ρ=0.7 (m/sec)

Dedge(ρ=0.7~1.0) (m2/sec)

Dcore (ρ=0.4~0.7) (m2/sec)

Proceedings of ITC/ISHW2007

-1

10

-2

10

-3

10

-4

10

3.5

3.6 3.7 3.8 3.9Rax (m)Neoclassical Anomalous
Minimum
Minimum

1

Lines at Te core=1.25keV (c)

0.5
0
-0.5
-1
-1.5

3.5

3.6

3.7 3.8 3.9Rax(m)
Neoclassical Anomalous
Minimum
Minimum

3.5

3.6

3.7 3.8
Rax(m)

3.9

10

10

10

=0.5keVe edge

0

-1

-2

3.5

4

(a)

3.6

3.7 3.8 3.9Rax(m)
Neoclassical Anomalous
Minimum
MinimumLines at T

3(b)=1.0keVcore

OutwardLines at T

2
1
0
-1
-2
3.5

3.6

3.7 3.8
Rax(m)

3.9

IntwardD1

V at ρ=0.7 (m/sec)

10

edge

ρ=0.70and 1.00 (m2/sec)

Fig.6 Comparison between neoclassical and anomalous transport coefficients at high field (a) Dcore, (b) Dedge and (c)Vcore at high filed (Bt=2.8T for Rax=3.5m,Bt=2.75, 2.8T for Rax=3.6m, Bt=2.64T for Rax=3.75m, Bt=2.54T for
Rax=3.9m) Red and blue lines indicate the values at the same temperature. Neoclassical values were calculated by
DCOM code[1]Fig.7 Comparison between neoclassical and anomalous transport coefficients at high field (a) Dedge and (c) Vcore at
low filed (Bt=1.45T for Rax=3.53m,Bt=1.49T for Rax=3.6m, Bt=1.5T for Rax=3.75m, Bt=1.54T for Rax=3.9m) Red
and blue lines indicate the values at the same temperature. Neoclassical values were calculated by GSRAKE code[14]at Rax=3.5m, however experimental D was minimum at
Rax=3.75m. On the other hand as shown in Fig.7 (a), at
low field, neoclassical Dedge was minimum at Rax=3.53m,
but experimental Dedge was minimum at Rax=3.6m. There
are difference of the minimum configuration between
neoclassical and anomalous particle diffusivity. The core
convection both at high field and at low field became
smaller at more inward shifted configuration. However,inward directed convection cannot be explained byneoclassical calculation.

2.3 Possible role of turbulence on density profile
The inward directed pinch in tokamak was widely
observed and cannot be explained by ware pinch whencollisional frequency becomes smaller [8,15]. The role of
ITG/TEM turbulence was suggested [8,16]. In heliotron
configuration, recently, theoretical work was done toinvestigate role of ITG/TEM turbulence[17]. In ref. 17, thedirection of the quasi linear particle flux was estimated forthe peaked and hollow density profile for the magnetic
configuration of LHD. When density profile was hollow
quasi linear particle flux was directed inward, then, as
density profile becomes peaked, the direction of fluctuation
driven particle flux reversed to outward. Since, particle
source was negligible in the core region, particle flux
should be zero. Possible interpretation of the role offluctuation is as follows.
When density profile was hollow, particle flux driven by
ITG/TEM turbulence was inward directed. This inward
directed particle flux can be balanced with outward
directed neoclassical convection to satisfy the particle
balance. This is consistent with the results that diffusion
was anomalous and outward convection was comparablewith neoclassical when density profile was hollow [3].

Proceedings of ITC/ISHW2007

(a)

(b)

(c)

(d)

(e)

(f)

Fig.8 Comparison of (a), (b) ne and Te profile and (c), (d)fluctuation amplitude profile (k=0.1~0.6mm-1) and (e), (f)
ITG/TEM linear growth rate calculated by GOBLIN code[17]
When density profiles are peaked, particle flux can be
driven by turbulence only. This is also consistent both
diffusion and inward convection was anomalous forpeaked density profiles.
Turbulence was measured by two dimensional phase
contrast imaging [18,19] for hollow and peaked density
profile. As shown in Fig.8, clear difference of fluctuation
amplitude was observed. The linear growth rate of
ITG/TEM turbulence was calculated by the GOBLIN code[17]. As shown in Fig.8 (c), (d), dominant part of
turbulence existed at the location where linear growth rate
was positive as shown in Fig. 8 (e), (f). Figure 8 (c) and (d)showed fluctuation amplitude only. The turbulence driven
particle flux cannot be measured by using phase contrast
imaging. However, observed fluctuation can possibly drive
inward directed particle flux at hollow density profile andzero flux for peaked density profile.
3. Summary
The parameter dependence of density profile andparticle transport was studied in the wide range of
operational regime of LHD. Two different dependence on
ν*b of density peaking factor was found. One is the gradualincrease of peaking factor with reduction of ν*b at
Rax=3.5m, 2.8T, where neoclassical transport minimum inthe dataset. This is similar with tokamak behavior. The
other is decrease of peaking factor with decrease of ν*b.
This is observed in the other configuration and is particularin LHD. Smaller neoclassical may result in tokmak likebehavior. The electron temperature dependences of D and
V were investigated at around optimum neoclassicalconfiguration at Rax=3.5m, 2.8T, and Rax=3.6m, 2.75,2.8T.
The diffusion coefficient was one order magnitude larger
than neoclassical value at both configurations, however, Te
dependence was different. At Rax=3.5m, 2.8T, Te
dependence was stronger than ones at Rax=3.6m, 2.75,

2.8T. At neoclassical minimum configuration (Rax=3.5m,
2.8T), the convection velocity at ρ = 0.7 was inward
direction, which was not predicted by neoclassical theory.
On the other hands, at Rax=3.6m, 2.75,2.8T, theconvection velocity at ρ = 0.7 was inward directed at lower
Te and reverse to outward direction at higher Te. When theconvection velocity was outward directed, it wascomparable with neoclassical value. These indicates, at
neoclassical minimum configuration (Rax=3.5m, 2.8T),
both diffusion and convection was determined by theanomalous process, but at Rax=3.6m, 2.75,2.8T, diffusion
process was determined by the anomalous process,however convection was determined by neoclassicalprocess at higher Te. The present results shows neoclassicalminimum is not same as anomalous minimum. The
difference of the spatial profile of turbulence was observed,
which suggested role of ITG/TEM turbulence on density
profileAcknowledgements
This work was supported by the National Institute for
Fusion Science budget NIFS05ULHH511.

References
[1]
[2]
[3]

S. Murakami et al Nucl. Fusion 42 (2002) L19–L22
H.Yamada et al. Nucl. Fusion, 45, 1684 (2005)
K. Tanaka et al, FUSION SCIENCE ANDTECHNOLOGY 51 97 JAN. (2007)[4] K. Tanaka et al., Nucl. Fusion 46 (2006) 110.
[5] K. Tanaka et al., to be submitted to PFR.
[6] K. Narihara et al., Rev. Sci. Instrum. 72 (2001) 1122.
[7] H. Takenaga, K. Tanaka, K. Muraoka et al., to be submitted
Nucl. Fusion[8]
Angioni et al., Phys. Plasmas 10 (2003) 3225
[9] K. Miyamoto published by Iwanami Book Service Centre,
Tokyo 1997 Fundamentals of Plasma Physics andControlled Fusion.
[10] C. D. Beidler and W.N.G. Hitchon, Plasma Phys. Control.
Fusion 36 (1994) 317.
[11] M.Yokoyama at al., Journal of Plasma and Fusion
Research, 81,83, (2005)[12] V.Tribaldos,, Phys. Plsama 8, 1229, (2001)[13] H.Sugama, T-H. Watanabe, Phys. Plasmas 13, 012501,(2006)[14] C.D. Beidler and W.D. D'haeseleer, Plasma Phys. Control.
Fusion 37 463 (1995)[15] Hoang G.T. et al 2003 Phys. Rev. Lett. 90 155002-1[16] Hoang G.T. et al 2004 Phys. Rev. Lett. 93 135003[17] O. Yamagishi et al., Phys. Plasmas 14 (2007) 012505.
[18] C. Michael et al., Rev. Sci. Instrum. 77, 10E923-1(2006)[19] C. Michael et al.,to be published, Journal of Plasma andFusion Research