24D01
Development of Integrated Transport Code, TASK3D,
and its Applications to LHD Experiment
ヘリカルプラズマ統合輸送コードTASK3Dの開発と実験適用
Masayuki Yokoyama, Arimitsu Wakasa*, Ryosuke Seki, Masahiko Sato, Sadayoshi Murakami*,
Yuji Nakamura**, Atsushi Fukuyama*, and LHD Experiment Group横山 雅之, 若狹 有光*，關 良輔，佐藤 雅彦, 村上 定義*, 中村 祐司**、福山 淳*,
LHD実験グループ
National Institute for Fusion Science322-6 Oroshi, Toki 509-5292, Japan
核融合科学研究所 〒509-5292 土岐市下石町322-6*Department of Nuclear Engineering, Kyoto University
Yoshida-Honmachi, Sakyo-ku, Kyoto 606-8501, Japan京都大学大学院工学研究科 〒611-0011 京都市左京区吉田本町**Department of Energy Science, Kyoto UniversityGokasho, Uji 606-8501, Japan
京都大学大学院エネルギー科学研究科 〒611-0011 宇治市五ケ庄
The integrated transport analysis code for helical plasmas, TASK3D, has been developed both bymodifying TASK [1] modules to be applicable to three-dimensional magnetic configurations, and byadding new modules for stellarator-heliotron specific physics. In this talk, these module developments so
far are collectively introduced, and recent progress on the applications to LHD experiment are described.

1. Introduction
The Large Helical Device (LHD) experiments
have steadily expand the parameter regime ofhelical plasmas such as electron and ion
temperatures, beta value, electron density, pulse
length and total input energy to plasma in along-pulse operation as summarized in Ref. [2].
The wide-range applicability of the integrated
code is mandatory, and, in the mean time,
experimental verification of each module and its
integration should be performed by utilizing theexperiment database.
2. Outlook and Present Status of TASK3D
Development
Figure 1 shows the overview of module
components of TASK and TASK3D to show how
TASK3D has been extended and will try to deal
withstellarator-heliotron
specificandthree-dimensional equilibrium. The integration ofthese modules is in progress.
The radial transport aspect of TASK3D employs
the diffusive transport equation [module, TR] withthe local diffusivity (particle and heat) and theparticle and heat source/sink term. Taking
three-dimensional configuration’s impact into
account such quantities have been main focus ofmodule modification/supplement in TASK3D
development. In the following, a few examples aredescribed in brief.

[Neoclassical diffusion and radial electric field,
DGN/LHD, ER] The presence of the ripple
transport (so called 1/ diffusion) is specific feature
in non-symmetric magnetic configurations. The
ambipolarity of neoclassical (NC) particle fluxes
has been demonstrated to well describe thebifurcation nature of the radial electric field (Er) in
LHD and other helical plasmas [3,4]. Thus, it is of agreat importance to accurately calculate theneoclassical fluxes, and then Er. For this purpose,the diffusion coefficient database, DGN/LHD [5],has been prepared for a wide-range of equilibria byutilizing advantages of NC transport codes, DCOM[6] and GSRAKE [7]. This highly-accurate NC
module has made it possible to compare with thepower-balance analysis to elucidate the turbulent
transport contribution [8].
[Time evolution of iota (current) profile, EI] The
three-dimensional magnetic configuration’s impact
on the current evolution through the susceptancematrix components is formulated [9]. The evolutionof the rotational transform profile evaluated throughthis current evolution equation is compared to show
the same trend (even quantitatively) with Motional
Stark Effect (MSE) measurement.
[NBI deposition analysis, FIT3D, MORH] As
for the NBI deposition analyses, FIT3D code [10]

has been routinely employed in LHD experimentalanalysis. To examine the impact of re-entering
particles especially for high-beta and/or low
magnetic field conditions, new module (MORH[11]) has been developed based on the HINT
equilibria. Experimental verification has beenpursued.
3. Recent Progress on Applications to LHD
Experiments
The interpretive power-balance analyses package,TR-snap [12], has been developed based oncombinations, so far, of TR, VMEC and FIT3D andMORH modules. It has been applied to LHD
plasmas to evaluate heat diffusivity andinvestigated the impact of re-entering NBI particles
on it [12].
The predictive simulations on achievabletemperature (profiles as well) have been also
recently performed based on TR, VMEC, FIT3D,
ER and DGN/LHD modules (for neoclassicaldiffusion contribution) along with assumed
anomalous contribution to heat diffusivity [13]. The
dedicated experiment measuring profiles required
for relevant interpretive simulations was recently
conducted to validate/provide modification such
simulation results. The comparison between
predictive and interpretive simulations will be made,and presented in detail in [13].

LHD experiments have been steadily progressed.
Validation studies will be extensively made toincrease the predictability for future experiments
and even reactor plasma simulations.
Acknowledgments
This work has been performed with thesupport and under the auspices of the NIFS
Collaboration
Researchprogram(NIFS11KNTT008 and NIFS11KLPT001).
References[1] A.Fukuyama, http://bpsi.nucleng.kyoto-u.ac.jp/task/.
[2] A.Komori, H.Yamada et al., Fusion Science andTechnology 58 (2010) 1[3] K.Ida et al., Nucl. Fusion 45 (2005) 391.
[4] M.Yokoyama et al., Nucl. Fusion 47 (2006) 1213.
[5] A.Wakasa et al., Contributions to Plasma Phys. 50(2010) 582.
[6] A.Wakasa et al., J. Plasma Fusion Res. 4 (2001) 408.
[7] C.D.Beidler et al., Plasma Phys. Control. Fusion 36(1994) 317.
[8] A.Wakasa et al., 23rd IAEA-FEC (2010).
[9] Y.Nakamura et al., Plasma Fusion Res. 3, (2008)
S1058.
[10] S.Murakami et al., Trans. Fusion Technol. 27 (1995)
256.
[11] R.Seki et al., Plasma and Fusion Res. 5 (2010) 027.
[12] R.Seki et al., Plasma and Fusion Res. 6 (2011)
2402081.
[13] A.Wakasa et al., 23P046-P, in this conference.

4. Concluding Remarks
The development of integrated transport code,
TASK3D, and applications of combined modules toFig.1. An overview of module components of TASK and TASK3D. Modules, utilized/will beutilized for TASK3D, are denoted in bold characters. They are categorized to heating modules forLHD (NBI, ICH and ECH), stellarator-heliotron specific physics and three-dimensionalequilibrium. They have been developed piece-by-piece basis.