23P085-P
Simulation of the incident energy dependence on the effect of NBIin GAMMA 10
GAMMA 10におけるNBI効果の入射エネルギー依存性シミュレーション
Hideaki Ueda, Yousuke Nakashima, Katsuhiro Hosoi, Takashi Ishi, Kazuya Ichimura, Hisato
Takeda ,Satoru Kigure, Shigehito Takahashi, Satoru Hotaka, Kazuo Ookawa and Tsuyoshi Imai
上田英明, 中嶋洋輔, 細井克洋, 石井 貴, 市村和也,武田寿人, 木暮 諭, 高橋樹仁, 保髙 暁, 大川和夫, 今井 剛
Plasma Research Center, University of Tsukuba,
1-1-1 Tennoudai, Tsukuba, Ibaraki, 305-8577, Japan筑波大学プラズマ研究センター 〒305-8577 つくば市天王台1-1-1
Neutral Beam Injection (NBI) have been installed at the central-cell and anchor-cell for plasma heating andparticle fueling in GAMMA 10. The central-NBI is injected into ICRF-heated “high density mode” and“hot ion mode” plasmas. The increase in diamagnetism and electron line density was observedexperimentally. A numerical simulation model using particles and energy balance equations was developed
to investigate these modes and the effect of NBI heating in central-cell. This code is developed to evaluate
as a neutron source towards the neutron irradiation of the fusion materials. For DT fusion condition energy
dependence of NBI and high electron temperature for ECH is investigated

1. Introduction
It is an important to subject to increase theplasma temperature and density in magnetic
confinement plasma devices, such as tokomakand helical and tandem mirror devices. Neutral
Beam Injection (NBI) is a successful method forplasma heating and particle fueling [1-5].
The central-cell in GAMMA 10 is a simple
axisymmetric mirror whose length is 6m. Neutralbeam injection systems have been installed at theplug/barrier, anchor and the central regions asshown Fig.1. The central-cell NBI (NBI-c)system is used for main plasma heating andparticle fueling.
In order to investigate the reactor materials, aneutron irradiation experiment is required asreactor engineering. We have the technique andexperience of generation of high density andtemperature plasmas using the tandem mirror
device. It is necessary to perform thesimulation which neutron flux expected in thepresent devices.
High-density-mode is one of the operation
modes in GAMMA 10.This operation has highplasma density and low ion temperature. In orderto raise the plasma parameter as the neutron
source device, improvement in the NBI effect byhigh-density plasma production is required. The
objective of this study is to estimate a plasma
parameter required for nuclear fusion conditions
according to the energy effect of NBI at highdensity operation.

Fig. 1 Schematic illustration of the GAMMA 10

2. Simulation model
In order to explain the above experiment results,
a numerical simulation model was developed. The
model is composed of ﬁve diﬀerential equations
based on the eﬄux and inﬂux of particles andenergy in the central cell. The equations arespatially zero dimensional and are solved
numerically to simulate the time evolution ofplasma parameters in the central cell [1]. Eachequation as follows,( )()( ){ ( )

( )⟨
( )

( )

⟩
{

( )⟨
( )

( )
( )[{{( )for neutral particle density( )}⟨( )( )( )}⟨,

⟩ ]

⟩ }
⟩
( )
( )}⟨( )⟩( )( ){⟨⟩

⟨

⟩ }

( )

{

( )⟨( )}⟨
( )

( )

⟨( )

⟩ ]

𝑑( )

⟩

#210021 (high n mode)

⟩( )

𝑀(2)
for warm ion density( )( )[{,( )( )}{⟨( )⟨( )

( )

⟩ ]

( )

( )

𝑑

𝑀

for hot ion density

⟨⟩ }

( )

( )⟨⟩

( )

( )

𝑑( )

( )⟨⟩

( )

( )}

𝑑( )

( )

⟨( )

{( )

( ){( )⟩

for warm ion energy density𝑑for electron energy density

( )

( )

,
( )}{⟨⟩

( )}

( )

⟨( ){
𝑑( )

( )

,

Tw=4.5keV, Te=40eV

1.5

1.5x1011x10

225x10

21NBI

0.5

170

8x10

216x10214x10212x10210.2
0.10160

165

170

175
180
Time[ms]

1850190

Fig. 3 Comparison between experiment and simulationin high density mode

175
180Time[ms]18501901x10

228x10216x10214x10

212x1021

Th=20keV
Th=50keV
Th=100keV
Th=200keV
Th=500keV

NBI0( )}

22Energy density[eV m -3]

Diamagnetism [10 -4 Wb]#214394 (hot ion mode)

220

⟩ }

3. Simulation result
Fig. 2 and 3 shows and example of the comparison
between hot ion and high density mode. Although
DMCC fall in hot ion mode, DMCC rises during NBI
in high density mode. The simulation of the highenergy NBI was shown in Fig. 4 on the basis ofhigh density mode. In this simulation, initial iondensity
is decided to be0 m-3 andenergy is changed from 20 to 500eV. As shown in afigure, when energy was raised, it turned out that
DMCC continues going up during NBI for 10 to 20
ms.

165

0.31x1022( )}( ){0160

NBI

1.2x10( ){𝑑Tw=0.8KeV, Te=18eV0.4,

( )

( )

⟩

Diamagnetism [10 -4 Wb]( )[Energy density[eV m -3]

0Enelgy density [eV m-3]

( )Fig. 2 Comparison between experiment and simulation
in hot ion mode

0.005

0.01

0.015

0.02

0.025

0.03

Time[s]Fig. 4 Energy dependence on the effect of C-NBI

4. Summary and future plan
In this development of the simulation code, theeffect of C-NBI in GAMMA 10 is fairly
reproducible. As the energy of NBI increases, itturned out that DMCC rises significantly.
In the future, fuel spices are changed into
deuterium and the spices of the neutral beam ischanged into deuterium or tritium, and it evaluated
how much neutron flux can be generated in
GAMMA 10.
References[1] H. Ozawa and Y. Nakashima: Plasma and Fusion
Research, Volume 5 pp. S2084 (2011).
[2] A. Abdrashitov et al., Trans. Fusion Sci. Tech. 47,No. 1T, 27 (2005).
[3] A.C. Riviere: Nucl Fusion 11 (1971) 363.
[4] Y. Nakashima et al., J. Nucl. Mater. 313-316, 553(2003).
[5] Y. Nakashima et al., Trans. Fusion Sci. Tech. 47, No.
1T, 155 (2005).