24P145PHigh Current Operation
on Inertial Electrostatic Confinement Fusion Device with Ion Source
放電型プラズマ中性子源でのイオン源を用いた大電流運転
Keita Kamakura, Yasuhiro Ishikura, Koudai Fukuta, Naoya Yamashita Hodaka Osawa
and Masami Ohnishi
鎌倉慶太, 石倉康弘，福田鉱大，山下直也, 大澤穂高, 大西正視
Kansai Univ. 3-3-35, Yamate-cho, Suita-shi, Osaka 564-8680, Japan
関西大学 〒564-8680 大阪府吹田市山手町3-3-35
The Inertial Electrostatic Confinement Fusion (IECF) device is a neutron source which is used thedeuterium – deuterium fusion reaction. The glow discharge plasma from deuterium gas should be producedefficiently in the IECF device. Ion source is equipped for making high discharge current and high energy ofions. In this study, improved new cathode is tested for driving more ion from ion source. The cathode iscylindrical Skelton structure and designed by the aid of ion orbital calculation. The high current of 52A,
24kV and 1.0 Pa is achieved at the experimental test with the improved cathode in hydrogen gas. This highcurrent operation will lead to increase the collision of deuterium ion beam – deuterium ion beam. The
neutron production rate will be raised at low gas pressure area because of the counter collision of ion
beams.

2. Improved cathodeFigure 2 (a) shows the improved cylindricalcathode which width is 230 mm and diameter is
120mm. The base ring is set toward ion source andmakes the potential which attract the more ion
beam into the main chamber.

Diamond shaped
CathodeIon source
RF power supply(200W)

Plus power supply(80kV, 100A)

Anode(b) Schematic view(a) Appearance
Fig. 1. IECF device with ion source for high current operation
Discharge Voltage (kV)

1. Introduction
Inertial electrostatic confinement fusion (IECF)
device have been studied by many researchers.
The IECF device for high current operation at
Kansai University are shown in Fig.1 (a), and theschematic view is given by Fig. 1 (b). This device
consists of the vacuum chamber, the grounded
spherical anode and the skeleton wire frame
cathode (diamond shaped or cylinder shaped)
setting at the center, the vacuum pump, the gas
feeder, the power supply(80kV, 100A) for ion
acceleration and the RF ion source for the highcurrent operation. The deuterium gas of about 1Pa
is filled in the vacuum chamber. A pulse power
supply applies a high negative voltage greaterthan several ten kV to the cathode.
The glow discharge between the anode and thecathode produce the ions accelerated to thecathode. Some of them have the high energy
enough to cause the fusion events with thedeuterium molecules or themselves. The currentof 25A at 30kV, 1.0Pa is achieved at the previous
experiment in which the diamond shaped cathodeis used. The neutron production rate is about
7.2x104 (1/sec) as a steady state (plus of 20Hz, 6usec).

(a) Skelton-wire framed
cylinder cathode

Diamond cathode

Cylinder cathodeGas pressure (Pa)(b)

Discharge characteristiccompare with the diamondFig. 2. Discharge characteristic of improved cylinder cathode3. Experimental results and conclusion
The experimental result of fig.2 (b) shows thatthe discharge voltage of Cylinder cathode is lower
than the one of diamond shaped cathode. The highcurrent of more than 50A is flowed, the plus power
supply is limited the discharge voltage because of
shortage about watt performance. It means the newcathode is attract the ion beam effectively from theion source.