05aE38PGAMMA 10ダイバータ模擬実験に向けたMPD Jetの適用
Application of MPD Jet for Divertor simulation experiment in GAMMA 10
市村和也1、中嶋洋輔1、細井克洋1、武田寿人1、木暮諭1、高橋樹仁1、岩元美樹1、細田甚成1、清水啓太1、蒋佳希1、長屋孝信1、平田真史1、池添竜也1、大木健輔1、坂本瑞樹1、今井剛1、市村真1
ICHIMURA Kazuya1, NAKASHIMA Yousuke1, HOSOI Katsuhiro1,
TAKEDA Hisato1, KIGURE Satoru1, TAKAHASHI Shigehito, et al.
1

筑波大学プラズマ研究センター
1
PRC, Univ. of Tsukuba

GAMMA 10/PDX [1-3] is able to produce
end-loss flux of 100~400 eV ion temperature(relevant to tokamak SOL plasma [4]) with the helpof powerful ICRF heating and mirror confinement.
The high temperature of the end-loss flux is quite
useful to study PWI and divertor physics. Thus it isimportant to find operation mode of GAMMA
10/PDX which produces more energetic and dense
end-loss flux. Past research shows that the simplest
way to control the parameters of end-loss flux is tocontrol the power of ICRF. On the other hand, since
the mirror machine has open-ended magnetic field,
it is possible to inject plasma particles directly
along the magnetic field by using plasma gun suchas magneto plasma dynamic jet (MPD Jet). Suchuse of the MPD Jet can be new method to increase
and/or control the parameters of the end-loss flux
(Fig. 1). Objectives of this research are to find new
operation mode and to expand the range of plasma
parameters of GAMMA 10/PDX tandem mirror byusing the MPD Jet.
Two MPD Jet systems of 6 MW dischargeenergy are mounted in the end-cells (east end-celland west end-cell) of GAMMA 10/PDX. In
standard operations, the MPD Jet systems are usedfor startup of the initial target plasma. In our newoperation mode, instead of the MPD Jet, the initial
target plasma is ignited by electron cyclotron
resonance heating (ECRH) [5]. After the start up, adense plasmoid is injected into the mirror confinedplasma by east MPD Jet. It was found that theplasma parameters in the new start up mode arealmost the same as in standard operations. It wasalso observed that the particle flux to west end-cell
was increased by east MPD Jet, which means thatthe plasmoid penetrated the ICRF plasma andreached to the other end-cell. As the results of east
MPD injection, plasma density of the east
anchor-cell was increased by 80% and the end-loss

flux to the west was almost doubled (Fig.2). Theseresults indicate that application of the plasma
injection by MPD Jet into the tandem mirror can bea powerful tool for studies of PWI and divertor
plasmas. In the presentation, we will show thedetailed results of the MPD Jet injection experimentand we will discuss effectiveness of the MPD Jet
for increasing the end-loss flux in GAMMA 10.

Figure 1 Schematic view of GAMMA 10/PDX
vacuum vessels. Locations of MPD Jet, Mirror
Confined Plasma, End Loss Flux, ECRH, and main
diagnostics are shown as arrows.

Figure 2. Ion Current signal measured by
ELIEA in the west end-cell. The effect of MPD
injection is seen at t = 101.5 ms.
References:[1] Y. Nakashima et al., Fusion Eng. Design 85(2010) 956-962.
[2] Y. Nakashima et al.,Trans. Fusion. Sci. Technol.
59 (2011) 61-66.
[3] Y. Nakashima et al., J. Nucl. Mater. 415 (2011)s996-s1000.
[4] K. Shimizu et al., Plasma Fusion Res. 80 No.3
(2004) 183-189.
[5] H. Shidara et al., Fusion Eng. Design 86 (2011)913-915.