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In the JT-60 tokamak at JAERI, an environment for remote participation is planning to be developed by concentrating ideas of experts of nuclear fusion research from research organizations and universities distributed throughout the country. We are constructing a hierarchical collaborative remote research system, which consists of remote experiment, remote analysis and remote diagnostic. In remote collaboration, it is important to share information, atmosphere and presence between the participants as well as to maintain the security of the system. To implement a collaborative environment, a video conferencing system, a video streaming system and remote analysis system called “VizAnalysis” have been developed for the communication. To assist the remote participation for the fusion research, the document management system based on the web browser called “VizSquare” has been developed. In JT-60, security and authentication methods utilizing a computer network and a new communication tool have been developed, and they are applicable to the remote participation of ITER.

Data processing system for JT-60 is constructed by mini-computers, microcomputers and CAMACs for the control and the data acquisition of plasma diagnostics. However, it is difficult to apply this system to the remote diagnostics using the internet, because the old microcomputers used for over 15 years has no internet connectivity. Therefore, the data processing subsystem using mini-computers and microcomputers should be replaced, keeping the consistency with the main computer. The workstation based on UNIX-OS is a useful candidate for replacing those computers, since it is excellent in the network communication, the cost and the stability. We therefore the replaced microcomputers controlled and monitored the diagnostic CAMAC system, and executed its data acquisition. The new workstation-based system was simple system, which consisted of the serial highway driver module for controlling CAMAC and CPU module with SPARC CPU in VMEbus. By these replacements, the difficulty in the remote control has been solved by using the network and screen control of X Window. The maintainability is also improved and the function enhancement becomes easier. In this paper, basic design for replacing mini-computer and microcomputer with the UNIX workstation will be described.

The JT-60U data processing system is a large computer complex gradually modernized by utilizing progressive computer and network technology. A main computer using state-of-the-art CMOS technology c...

The JT-60 data processing system is a large computer complex, gradually being modernized by utilizing progressing computer and network technologies. There were three major changes in our system recently. A VME-based fast data acquisition system (FDS) has been developed to enlarge a transient mass-data storage system (TMDS). It can acquire the data of 6 MB per channel with 1 or 5 μs sampling. Now there are three FDSs with 29 channels. The TMDS, which was composed of a mini-computer and 61 channels of 6 MB memory modules with 5-μs sampling, has been replaced with a new system based on the technology of the VME-based fast data acquisition system. One of the outdated auxiliary crate controllers with micro-processor (ACM), which controls CAMAC modules in the crate on the serial highway, acquires data from them and transfers data to the main computer, has been replaced by a workstation with a VMEbus byte-serial highway driver. The combination of a workstation and a VMEbus byte-serial highway driver has been developed and used to replace many mini-computers in our system. A workstation with a digital linear tape (DLT) library has been introduced as final data storage. The conversion of a few terabytes of raw data tapes for a cartridge tape library (CTL), which is attached to a mainframe computer, Fujitsu GS8300, will be started by using data conversion software prepared to handle mainframe data on the workstation.

The JT-60 data processing system is a large computer complex and gradually modernized by utilizing progressing computer and network technology. There are two major changes in our system. A main computer of FACOM M-780 has been replaced with compatible GS8300 using state-of-art CMOS technology, which results in lower power and space usage with nearly the same performance. Now it can handle ∼500 MB of data per discharge. A gigabit ethernet switch with FDDI ports has been introduced to cope with the increase of handling data. The switch will connect a tera-byte (TB) data server at the bandwidth of a gigabit per second with the main computer and many data acquisition workstations. Other developments in our system are the realization of three workstation-based plans, the TB data server, the VME-based fast data acquisition system and a CICU. The TB data server is basically a UNIX workstation with ∼100 GB RAID disks and ∼900 GB MO auto-exchangers. The VME-based fast data acquisition system has been developed to enlarge the present TMDS. The CICU, which has a function of interfacing the main computer with the CAMAC system, has been replaced with the workstation-based system after the fine tuning.

The JT-60 data processing system was originally a large computer complex system including a lot of micro-computers, several mini-computers, and a mainframe computer. Recently, several improvements have been made to the original system to modernize the system. Many sub-systems composed of aged mini-computers have been replaced with workstations by utilizing recent progress in computer and network technologies. The system can handle ∼300 MB of raw data per discharge, which is three times larger than the amount in the original system. These improvements have been applied to develop element technologies necessary to the remote participation in JT-60 experiments. A remote diagnostics control and monitoring system and a computer system for access to JT-60 data from the Internet are used together with video conferencing systems for a real-time communication. In 1996, the remote participation based on them was successfully demonstrated in collaboration with Japan Atomic Energy Research Institute, Los Alamos National Laboratory, and Princeton Plasma Physics Laboratory.

Fusion performance of reversed shear discharges with an {ital L}-mode edge has been significantly improved in a thermonuclear dominant regime with up to 2.8 MA of plasma current in the JT-60U tokamak. The core plasma energy is efficiently confined due to the existence of persistent internal transport barriers formed for both ions and electrons at a large minor radius of r/a{approximately}0.7 near the boundary of the reversed shear region. In an assumed deuterium-tritium fuel, the peak fusion amplification factor defined for transient conditions involving the dW/dt term would be in excess of unity. {copyright} {ital 1997} {ital The American Physical Society}

The effects of chitosan (CS) intake on faecal microbiota and faecal metabolites were studied in eight healthy volunteers who consumed a mixed free choice diet (control diet) for 2 wks before and after CS intake (CN-1 and CN-2 period, respectively), and the same diet with an additional 3 g CS/day for 1 wk (CS-1 period) and 6 g CS/day for 1 wk (CS-2 period). During CS intake, there was no detectable change in the concentrations of the microorganisms examined throughout the experimental periods. However, the frequency of occurrence of lecithinase-negative clostridia decreased significantly (P

In the data processing system for the JT-60 tokamak, a unique mass data acquisition system with fast sampling, a transient mass data storage system (TMDS), has been used since 1988. It is composed of a minicomputer and 61 channels of 4/6 MB memory modules with a sampling rate up to 200 kHz and about 300 MB of data are transferred to a main computer by using a special LAN developed by Fujitsu Ltd. TMDS can handle a large amount of data, but cannot be enlarged in its capability, such as CPU power or the number of channels. To solve the problems of TMDS, a new fast VME data acquisition system (FDS), has been developed. It can acquire 6 MB of data per channel with a sampling rate of 200 kHz or 1 MHz and consists of a workstation with VMEbus memory modules. Up to now there are three FDSs with 24 channels. The minicomputer of TMDS has been replaced with a new system based on the technology of FDS. To cope with mass data transfer to a data server, they are connected with a gigabit ethernet switch.

Since 1996, the remote participation in JT-60 experiments has been successfully conducted in collaboration with JAERI, Los Alamos National Laboratory and Princeton Plasma Physics Laboratory. The remote analysis system is a computer complex consisting of an analysis server and a data server for access to JT-60 data. Collaborators of the remote participation can analyze JT-60 data by using this system through the Internet. For the remote diagnostic system, an X Window control program has been customized to communicate via the overseas line using a UNIX workstation at the remote site and one in the JT-60 control room. It has a feature of real-time remote control of diagnostic equipment and remote access to CAMAC data. Both systems are used together with the ISDN-based video-conferencing system for real-time communication between the remote laboratory and the JT-60 control room.

Recent lower hybrid current drive (LHCD), and heating (LHH) experiments on JT-60 are reported. The current drive product of neRpIRF approximately 12.5*1019 m-2 MA was achieved at the LH power of approximately 4.5 MW, and the CD efficiency, the energy confinement, the global power balance and the heat load on divertor plates were investigated in high power LHCD plasmas. Nearly steady state H-mode discharges were found during LHCD with two different frequency injections. Sawtooth suppression in NB heated plasmas by LHCD have shown an improvement in confinement near the plasma center. Parametric instabilities in LH heating experiments were significantly reduced by increasing the plasma current, and the stored energy increased linearly with heating power of up to approximately 9 MW at ne approximately 7*1019 m-3 and Ip=2.75 MA. Parametric instabilities near the plasma edge in the ion heating regime were also reduced in peaked density plasmas produced by pellet injection and LH waves increased the central plasma pressure at ne(0) > 1.4*1020 m-3.

After injecting 100 ml of a saline solution into the hepatic artery of 27 livers evidencing a hepatocellular carcinoma, samples from the resected livers were collected through the portal and the hepatic vein. Cancer cells were detected in 4 out of 27 samples from the portal vein and in 1 out of 19 samples from the hepatic vein, and the total number of positive cases were 4. Further, tumors over 5 cm in diameter showed a tendency of flowing cancer cells into the portal vein. Four positive cases had an intrahepatic and a distant metastasis within one year of their operation and two of these patients died.

In the last year, ohmic heating experiments were performed in JT-60 for about three months; May–June 1985 and March 1986. The major experimental effort has been concentrated on the divertor configuration in anticipation of H-mode operation of JT-60 in high power supplementary heating experiments starting in August 1986. Stable discharges with a divertor have been obtained at Ip = 1.85 MA and ne = 5.7 × 1019m−3. Radiated power from the main plasma in divertor discharges is reduced to one third of that in material limiter discharges. The electron density has a broad radial profile and the effective safety reaches qeff = 2.5. The neutral gas pressure in the divertor chamber becomes significantly high and the control of particle recycling has been attempted.

小腸Crohn病で,稀な合併症といわれている穿孔性腹膜炎をきたし,緊急手術にて救命し得た2症例を経験したので,若干の文献的考察を加え報告する.症例1は,34歳男性.急激な腹痛にて来院し,腹部単純X線にて遊離ガス像が認められ,穿孔性腹膜炎の診断で緊急手術を施行した.回盲部より口側約50cmの回腸腸間膜付着側に穿孔が認められ回腸を約80cm切除した.切除標本は肉眼的,組織学的にCrohn病であった.症例2は,42歳男性.腹部膨満を主訴に,腸結核の疑いにて入院した.入院後2日目に激烈な腹痛が出現し,穿孔性腹膜炎の診断で緊急手術を施行した.Treitz靱帯より約3mの回腸の腸間膜付着側に穿孔が認められ,小腸を約150cm切除した.切除標本は肉眼的,組織学にCrohn病であった.Crohn病の穿孔はまれで,本例はそれぞれ本邦における16例目,17例目の報告例である.

Diagnostic instruments for measuring the JT-60 plasma are fully developed and ready to operate. Each instrument and its fundamental characteristics are described as well as some aspects of the plasma parameters. The new features in JT-60 diagnostics are that the diagnostics system which has its own data processing system separate from the machine control computer, and the utilities for each diagnostics instrument (vacuum, electricity, water, air, liquid nitrogen) constitute one system in the total diagnostics system.

Emphases in JT-60 experiments are placed on (1) lower-hybrid (LH) current drive characteristics with a multi-junction type launcher, and (2) the confinement study with combination of neutral beam injection LH current drive and pellet injection. The new multi-junction LH launcher provides a sharp N/sub /// spectrum with high directivity for N/sub ///=1-3.4. The current drive efficiency and the radial distribution of high energy electron production show clear correlation with injected N/sub ///: the current drive efficiency has the maximum at low N/sub ///( approximately 1.3) while flattening of plasma current is more effective in large N/sub ///. A broad radial distribution of high energy electron current and approximately 30% reduction in sawtooth inversion radius were obtained by high N/sub /// ( approximately 2.5) LH injection. To fully suppress the sawtooth activity, low N/sub /// ( approximately 1.3) injection was found to be more effective. Improved energy confinement has been obtained with hydrogen pellet injection. Energy confinement time was enhanced up to 40% relative to usual gas fuelled discharges. The discharge has a strongly peaked electron density profile with ne(0)/(ne) approximately 5 and ne(0) approximately 2.0*1020 m-3. The improved discharges are characterized by a strongly peaked pressure profile within the q=1 magnetic surface, and degrades when a large sawtooth recovers or the pressure gradient may reach a critical value. When large (3 mm, 4 mm) and fast (2.2 km/s) pellets were injected, 30% energy confinement improvement was obtained even during the NB heating of 14 MW. Further investigations of IDC characteristics have been made. The oxygen impurity lines from the main plasma and the main radiative loss drop first. Then the plasma stored energy starts to rise. The particle recycling is reduced around the main plasma, and is localized in the neighborhood of the X-point with a time lag of approximately 0.2 sec. Eventually the discharge shows a significant remote radiative cooling power at the divertor region.

Initial ohmic heating experiments in JT-60 were performed for a three month period of April-June 1985. A maximum plasma current of 1.6 MA was obtained for both divertor and limiter discharges. Low-q discharges of qeff=2.5 and high density discharges of 4.8*1019 m-3 in line-averaged density were obtained in the divertor configuration. In divertor discharges radiated loss from the main plasma can be kept at 20-30% of the ohmic input.

Essential divertor functions — density and energy control — have been investigated in the JT-60 divertor with metal walls. Neutral pressure in the divertor chamber increases in proportion to n2e and high recycling state for particle exhaust is realized. At ne ≤ 6 × 1019m−3, wall pumping by the divertor plates is dominant in particle exhaust. However, at ne ≥ 6 × 1019m−3, particle exhaust by active divertor pumping systems becomes essential. Because of the effectiveness of the divertor, radiation loss in the main plasma is reduced to 5–10% of the absorbed power and impurity concentrations are significantly suppressed at very low level (Zeff = 1.5-2.0). In the experiments with graphite walls, short periods of H-mode phases were found in the outside X-point divertor discharges although improvement in energy confinement is limited to within 10%. In limiter discharges, combination of high vessel temperature (210–300 °C) and low current limiter discharges (1.5 MA) without gas puffing is effective as a wall conditioning in obtaining reproducible high density discharges. The maximum parameters, Ip = 3.2 MA, ne = 1.2 × 1020m−3, qeff = 2.2 at Bt = 4.8T, a Murakami parameter of 7.5, and a stored energy of 3.1 MJ have been attained. The maximum density is limited by the occurence of the MARFE. During high power neutral beam heating, enhanced carbon influx was observed possibly due to chemical sputtering. The wall pumping by the inner wall is still effective in decreasing the electron density from the high density region of ne ~ 1 × 1020m−3. An empirical energy confinement scaling of JT-60 has been drawn in terms of an offset linear function as τE = 0.19 I1.9PPabs + 0.062 a1.8p

From June to October 1987, JT-60 achieved fusion product (ne(0). tau E*.Ti(0)) of 6*1019 m-3.keV.s with hydrogen plasma at plasma current of 2.8 to 3.1 MA with neutral beam power of approximately 20 MW. The central electron density of 1.3*1020 m-3 was obtained at plasma current of 3 MA with 13 approximately 20 MW neutral beam power and the confinement time reached 0.14-0.18 s. An offset linear scaling law like the Shimomura-Odajima scaling on confinement time will be able to reproduce experimental data better than that of the Goldston type scaling. With low beam energy injection approximately 40 keV, confinement degradation was found. Many short periods (0.05 approximately 0.1 s) of H-mode phase were found in outside X-point divertor discharges with NB or NB+RF(LH or IC) heating power above 16 MW. However, improvement in energy confinement time was limited to 10 %. The ballooning/interchange stability analyses were also made for the outside X-point divertor equilibrium in connection with H0-phase capability. Heating powers of 9.5 MW and 1.9 MW were obtained by LHRF, ICRF injection, respectively. In combined LHRF and NB heating, the incremental energy confinement time of 0.064 s was obtained, which is the same level of that of NB heating only. In combined NB and on-axis ICRF heating of low ne discharge, an incremental energy confinement time of 0.21 s was obtained, which is three times as long as those of NB or ICRF heating only. High energy beam ions were accelerated by ICRF in the central region of the plasma.