5. SUMMARY OF AVAILABLE EQUIPMENTS
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- Announcement for Joint Research Proposals, 2025
- 5. Summary of Available Equipments
5-2. Nuclear Fusion Dynamics
(1) QUEST (2) Research Facilities for Nuclear Materials
(3) Research Facilities for Plasma facing Materials for Fusion Reactor
(4) Plasma Assembly for Nonlinear Turbulence Analysis (PANTA)
( 1 ) QUEST
Contact : Hiroshi Idei
Spherical tokamak can realize higher beta value than that of Tokamak. The QUEST research project is planned to pioneer new long-pulse-operation regime and establish its academic base. We aspire for leading research to development of advanced nuclear fusion reactors. Long-pulse-operation of tokamak is an essential theme not only seeking steady state tokamak reactor but also providing new findings for the invention of magnetic fusion reactor. Our group has proposed research topics as follows:
- To demonstrate and establish new methods to drive plasma current by electromagnetic waves and mode-converted electrostatic waves.
- To improve diverter concepts and to establish the way of controlling particles and heat loads during long pulse operation.
- To comprehensively establish recycling control based on wall temperature adjustment and advanced wall control under high plasma performance.
Our target parameters are;
- Phase I :
- (quasi-steady state : Plasma current Ip = 20-30 kA, Input RF heating power PRF = 450 kW)
- Phase II :
- (quasi-steady state : Ip = 100 kA, , ne = 0.4×1019 m-3, PRF = 1 MW)
(Pulse : Ip = 300 kA, ne = 0.4×1019 m-3, PRF = 3 MW)
| Parameters | Design | Accomplished |
|---|---|---|
| Major radius | 0.68 m | 0.68 m |
| Minor radius | 0.40 m | 0.40 m |
| Aspect ratio | 1.7 | 1.4 |
| Elongation | 1.6 ~ | 1.2 |
| Troidal field | 0.25 T (at R=0.6 m, steady state) 0.5 T (at R=0.6 m, Pulse) |
0.25 T (at R=0.6 m, steady state) |
| Plasma current | 20 kA (Phase I) 120 kA (Phase II) |
120 kA (Pulse) |
| Duration time | Steady state | 6 h (2 kA) |
| Vacuum Vessel | Outer Diameter d = 2.8 m Height h = 2.8 m |
High temperature wall installed. (100-500 ℃) |
Current Drive Devices
| Specification | |
|---|---|
| Frequency | 8.56 GHz |
| Klystron | 1 systems |
| Output power | < 250 kW |
| Pulse | CW (controlled by input pulse) |
| Vacuum window | Sapphire |
| Specification | |
|---|---|
| Frequency | 28 GHz |
| Gyrotron | 1 systems |
| Output power | < 200 kW |
| Pulse | < 1.6 s |
| Vacuum window | Sapphire |
Measurement
| Device | Target | Information |
|---|---|---|
| Flux loop | Plasma position control | |
| Magnetic probe array | Mag.field，Mag.fluctuation | |
| Multi-channel visible spectrometer | Profile measurement of line emission | Spectrometer (Focal distance：1m) Cooled CCD |
| Visible monochrometer | Ionization, Zeff, impurity in plasma | P-250 |
| Microwave interferometer | Line-averaged electron density | |
| Thomson scattering | Electron temperature, density | 10 Hz |
| Movable SOL probe | Density and temperature in SOL | |
| Gas injection system | Gas puff, Mass flow meter | H2, He |
| Ionization gauge | Fast ion-gauge | |
| X-ray pulse height analyzer | X-ray energy spectrum | |
| High speed camera | Monitoring Plasma cross-section | Photron Nova S6 |
| Specification | |
|---|---|
| Number of channels | 4 ch |
| Number of energy channels | 1024 ch |
| Energy resolution | ～ 1.2 keV ＠122 keV |
| Sampling time | > 1 ms |
| Energy range | 30 ～ 200 keV |
| Specification | |
|---|---|
| Oscillator | Frequency multiplier (9.3 -> 75 GHz) |
| Model | AMC-12RHOA |
| Frequency | 75 GHz |
| RF output | 0.2 W |
| Interferometer type | Heterodyne |
| Detectors | Harmonic mixer, IQ detector |
| Specification | |
|---|---|
| Focal distance | 250 mm |
| Aperture | F = 4.5 |
| RLD | 30 Å/mm |
| Resolution | 0.6 Å (FWHM at 5460.74 Å) |
| Specification | |
|---|---|
| Material | Tungsten |
| Melting point | 3387 ℃ |
| Electrodes | Depending on the probe head |
| Probe voltage | -100 ～ 100 V |
| Sweep frequency | 1 kHz |
| Number of channels | Depending on the probe head |
| Specification | |
|---|---|
| Spectrometer | Acton AM-510 |
| Model | Czerny-Turner |
| Focal distance | 1 m |
| Aperture ratio | F/8.7 |
| RLD | 7.4 Å/mm |
| Wave length range | 1850-8000 Å |
| Resolution | 0.12 Å |
| Detector | ICCD-1024MLD (Pertier Element) |
| CCS effective area | 23.5 mm × 6.7 mm、 900 × 256 pixels |
( 2 ) Research Facilities for Nuclear Materials
Contact : Takeshi Ido
High Energy Ion Generating Apparatus
Tandem type 1MV Accelerator. This apparatus can be used for the non-destructive analyzing experiment, such as Elastic Recoil Detection (ERD), Rutherford Back Scattering (RBS), Channeling, Particle Induced X-ray Emission (PIXE), and for the irradiation experiment to produce damage to the specimen, which greatly contributes to the study of plasma facing materials and structural materials for the fusion reactor.
| Item | Specification |
|---|---|
| High voltage | Cockcroft-Walton |
| Available Terminal Voltage | 0.1 - 1.0 MV |
| Maximum Beam Current | 4He2+ 0.5 puA (3.0 MeV), 58Ni3+ 2.0 puA (4.0 MeV) |
| Analysis Function | Rutherford Back Scattering (RBS) Channeling Elastic Recoil Detection (ERD) Particle Induced X-ray Emission (PIXE) |
| Irradiation Capacity | High Dose Irradiation by Heavy Ion (~ 100 dpa) |
| Irradiation Temperature Range | RT ~ 800℃ |
( 3 ) Research Facilities for Plasma Facing Materials for Fusion Reactor
Contact : Kazutoshi Tokunaga
Thermal Desorption Spectroscopy system (TDS)
Thermal Desorption Spectroscopy (TDS) is used to investigate desorption gas from a heated sample using a mass spectrometer. Information about identification of molecules, the amounts of adsorbed molecules and process of desorption on the surface is obtained.
| Item | Specification |
|---|---|
| Mass Spectrometer | Quadrupole M.S.(SEM : 1 ~ 100 a.m.u.) |
| Temperature | ~ 1400 ℃ |
| Sample size | 0 mm x 10 mm x 50 mm (max.) |
( 4 ) Plasma Assembly for Nonlinear Turbulence Analysis (PANTA)
Contact : Akihide Fujisawa
The linear magnetized plasma experiment PANTA (Plasma Assembly for Nonlinear Turbulence Analysis) is available for the basic study of plasma turbulence. PANTA creates a linear plasma column with overall length 4 m and radius 6 cm. An advantage is the ultra-multi-channel Langmuir probe system which allows spatiotemporal structure (e.g. the streamer) measurement of plasma turbulence with high spatial and temporal resolutions.
| Item | Specification |
|---|---|
| Vacuum Vessel | diameter = 0.45 m, overall length = 4 m, Background pressure ~ 1 x 10-4 Pa |
| Plasma Production | Helicon wave power source (1 - 10 MHz, 10 kW), Electron cyclotron wave power source (2.45 GHz, 5 kW) |
| Plasma Parameter | Helicon-Ar-plasma : electron temperature ~ 2-4eV Electron density ~ 0.2 x 1019 m-3, magnetic field < 0.15 T |
| Diagnostics | Manometer, Quadrupole mass spectrometer, Langmuir probe array (spatial resolution ~ 4 mm, temporal resolution ~ 1 μsec, Total 192ch available) |
