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In LHD discharges, the NBI heated plasmas are terminated in two ways: (a) thermal decay (TD) after the termination of NBI and (b) radiative collapse (RC) during the NBI heating. The basic characteristics of the TD and RC discharges are compared. It is found that the decay and collapse of the plasma are mainly governed by the heating power and the plasma density. The critical density c for the collapse of RC plasmas is similar to the scaling laws obtained in other helical devices, i.e. c∝(PB/V)0.5, where P, B and V denote heating power, magnetic field and plasma volume, respectively. Moreover, measurements using multichannel bolometric diagnostics indicate that the total radiation profiles in TD and RC plasmas are usually inboard-outboard symmetric and asymmetric, respectively, at the end of the discharge. In RC discharges, the total radiation profile develops in several phases. Before the onset of the thermal instability (TI), the radiation profile is rather symmetric, while after that, the radiation profile evolves from being symmetric in the initial period towards being asymmetric eventually with high radiation on the inboard side. Corresponding variations are shown in the time evolutions of the density and temperature profiles, and a substantial contraction of the plasma column is observed immediately after TI onset. The spatial and temporal coincidence of the asymmetries in the radiation, density and temperature is similar to that observed with multifaceted asymmetric radiation from the edge (MARFE) in tokamaks. But, unlike MARFEs, the asymmetric radiation (AR) in LHD is rather transient since it appears just before the end of RC discharges. The underlying cause for the development of radiation asymmetry was investigated and compared with existing instability models. The result suggests that the high inboard radiation is a manifestation of an enhanced local thermal instability, and the AR results from asymmetric developments of TI on the inboard-outboard sides during the final stage of RC discharges.

The experimentally optimized magnetic field configuration of the Large Helical Device [A. Iiyoshi et al., Nucl. Fusion 39, 1245 (1999)], where the magnetic axis is shifted inward by 15 cm from the early theoretical prediction, reveals 50% better global energy confinement than the prediction of the scaling law. This configuration has been investigated further from the viewpoints of high energy particle confinement and magnetohydrodynamic (MHD) stability. The confinement of high energy ions is improved as expected. The minority heating of ion cyclotron range of frequency was successful and the heating efficiency was improved by the inward shift. The confinement of passing particles by neutral beam injection was also improved under low magnetic field strength, and there could be obtained an almost steady high beta discharge up to 3% in volume average. This was a surprising result because the observed pressure gradient exceeded the Mercier unstable limit. The observed MHD activities became as high as beta but they did not grow enough to deteriorate the confinement of high energy ions or the performance of the bulk plasma, which was still 50% better than the scaling. According to these favorable results, better performance would be expected by increasing the heating power because the neoclassical transport can also be improved there.

Experimental studies of the impact phenomena between a magnetic fluid drop and the rough solid surface under applied magnetic fields were performed using a high speed digital video camera system. The direction of applied magnetic fields are perpendicular to the target plane. Effects of the target roughness on the impact phenomena were found to be important for the spreading process of magnetic fluid flow. It was also found that the formation of spikes on the impact pattern left by magnetic drops is not clear at higher values of the roughness number.

The extreme ultraviolet spectra of C VI have been studied for a Neutral Beam Injection (NBI) plasmas in Large Helical Device (LHD). A strong distortion in the population distribution over the excited levels was observed and we conclude that is caused by charge-exchange recombining (CXR) processes between C^6+ ion and recycling neutral hydrogen. Spatially resolved measurements show that the C^6+-H CXR processes take place in the plasma peripheral region in LHD. We have taken a CXR pan of C VI 1s-4p line using the result of a calculation code.

This paper is concerned with the functional design and hydrodynamic characteristics of fish scales. The rough surfaces of fish scales were measured with a three-dimensional, optical shape measuring system. The measurement was carried out on embiotocid fish Ditrema temminck, rockfish Sebastes inermis, and dogfish Mustelus manago Bleeker. Some scales of a dogfish Mustelus manago Bleeker were also observed microscopically making use of the scanning electron microscope as a faster fish. From the viewpoint of hydrodynamics, the microscopic structure and morphological characteristics of fish scales were discussed.

This paper reports on the behaviour of high-energy ions created by ion cyclotron range of frequency (ICRF) heating on the Large Helical Device (LHD). In the third experimental campaign conducted in 1999, it was found that minority heating has good heating performance, and high-energy particles were observed. In the fourth campaign in 2000, the temporal behaviour of high-energy ions was investigated in the minority heating regime using turnoff or modulation of ICRF power. The time evolution of the high-energy particle distribution was measured using a natural diamond detector (NDD) and a time-of-flight neutral particle analyser (TOF-NPA). It was found that the count number of higher-energy particles declines faster than that of lower-energy particles after ICRF turnoff. In the modulation experiments, the phase difference of the flux of high-energy particles with respect to the ICRF power modulation increased with energy. These results were explained qualitatively by the Fokker-Planck equation with a simple model. The pitch-angle dependence of the distribution function was also measured in the experiment by changing the line of sight of the TOF-NPA, and an anisotropy of the high-energy tail was found. This anisotropy was reproduced by solving the bounce-averaged Fokker-Planck equation. The second harmonic heating was conducted successfully for the first time in the LHD in high-β plasma, and high-energy particles were also detected in this heating regime.

The java -based real-time monitoring system has been in use at the National Institute for Fusion Science, Japan, since the end of March 1988 to maintain stable operations. This system utilizes java technology to realize its platform-independent nature. The main programs are written as java applets and provide human-friendly interfaces. In order to enhance the system's easy-recognition nature, a 3D feature is added. Since most of the system is written mainly in java language, we adopted java 3D technology, which was easy to incorporate into the current running systems. With this 3D feature, the operator can more easily find the malfunctioning parts of complex instruments, such as LHD vacuum vessels. This feature is also helpful for recognizing physical phenomena. In this paper, we present an example in which the temperature increases of a vacuum vessel after NBI are visualized.

During the first two years of the LHD experiment the following results have been achieved: (i) higher Te (Te(0) = 4.4 keV at ne = 5.3 × 1018 m-3 and Pabs = 1.8 MW); (ii) higher confinement (τE = 0.3 s, Te(0) = 1.1 keV at ne = 6.5 × 1019 m-3 and Pabs = 2.0 MW); (iii) higher stored energy, Wpdia = 880 kJ at B = 2.75 T. High performance plasmas have been realized in the inward shifted magnetic axis configuration (R = 3.6 m) where helical symmetry is recovered and the particle orbit properties are improved by a trade-off of MHD stability properties due to the appearance of a magnetic hill. Energy confinement was systematically higher than that predicted by the International Stellarator Scaling 95 by up to a factor of 1.6 and was comparable with the ELMy H mode confinement capability in tokamaks. This confinement improvement is attributed to configuration control (inward shift of the magnetic axis) and to the formation of a high edge temperature. The average beta value achieved reached 2.4% at B = 1.3 T, the highest beta value ever obtained in a helical device, and so far no degradation of confinement by MHD phenomena has been observed. The inward shifted configuration has also led to successful ICRF minority ion heating. ICRF powers up to 1.3 MW were reliably injected into the plasma without significant impurity contamination, and a plasma with a stored energy of 200 kJ was sustained for 5 s by ICRF alone. As another important result, long pulse discharges of more than 1 min were successfully achieved separately with an NBI heating of 0.5 MW and with an ICRF heating of 0.85 MW.

Neutral beam injection heated discharges at the density limit in the Large Helical Device [O. Motojima, H. Yamada, A. Komori et al., Phys. Plasmas 6, 1843 (1999)] are terminated with asymmetric radiative collapse (ARC) exhibiting several properties in common with the MARFE (multifaceted asymmetric radiation from the edge) phenomenon: (1) A highly poloidally asymmetric radiation profile which is stronger on the inboard side. (2) This asymmetry is well correlated with the signal from the multichord interferometer. (3) Moreover, evidence from several diagnostics at different toroidal locations supports the possibility that ARC may be toroidally symmetric. However in contrast to MARFE, ARC is only observed in the period just prior to the quench of the plasma.

A power modulation experiment was conducted in the third campaign of the LHD. In a conventional analysis of the modulation experiments, the energy confinement time and heating efficiency are taken as constant, disregarding their dependence on the plasma parameters. In this paper, their dependence on the plasma temperature and heating power is taken into consideration to improve the analysis of the power modulation experiments. Several models, with differing dependence on the plasma parameters, have been examined. There have been several reports suggesting that the transport coefficients obtained from the dynamical method are different from those obtained from power balance analyses. This paper finally concludes that the energy confinement time obtained from the power modulation experiments well agrees with that obtained from the power balance analysis, made including temperature dependence both in energy confinement time and heating efficiency.

The energy confinement and thermal transport characteristics of net current free plasmas in regimes with much smaller gyroradii and collisionality than previously studied have been investigated in the Large Helical Device (LHD). The inward shifted configuration, which is superior from the point of view of neoclassical transport theory, has revealed a systematic confinement improvement over the standard configuration. Energy confinement times are improved over the International Stellarator Scaling 95 by a factor of 1.6 ±0.2 for an inward shifted configuration. This enhancement is primarily due to the broad temperature profile with a high edge value. A simple dimensional analysis involving LHD and other medium sized heliotrons yields a strongly gyro-Bohm dependence (τEΩ ∝ ρ*-3.8) of energy confinement times. It should be noted that this result is attributed to a comprehensive treatment of LHD for systematic confinement enhancement and that the medium sized heliotrons have narrow temperature profiles. The core stored energy still indicates a dependence of τEΩ ∝ ρ*-2.6 when data only from LHD are processed. The local heat transport analysis of discharges dimensionally similar except for ρ* suggests that the heat conduction coefficient lies between Bohm and gyro-Bohm in the core and changes towards strong gyro-Bohm in the peripheral region. Since the inward shifted configuration has a geometrical feature suppressing neoclassical transport, confinement improvement can be maintained in the collisionless regime where ripple transport is important. The stiffness of the pressure profile coincides with enhanced transport in the peaked density profile obtained by pellet injection.

A novel technology is suggested for making solid hydrogen shells around impurity pellets to be injected into plasmas of fusion devices with a view to looking into its transport properties. In proof-of-principle tests, a 3 mm long and 3 mm diameter cylindrical solid hydrogen shell was formed around a 0.2 mm diameter globular pellet at a temperature of 8–11 K within 5 min and accelerated in a pipe-gun barrel up to 1 km/s.

Pellet injection has been used as a primary fuelling scheme in the Large Helical Device. With pellet injection, the operational region of NBI plasmas has been extended to higher densities while maintaining a favourable dependence of energy confinement on density, and several important values, such as plasma stored energy of 0.88?MJ, energy confinement time of 0.3?s, ? of 2.4% at 1.3?T and density of 1.1 ? 1020?m -3, have been achieved. These parameters cannot be attained by gas puffing. Ablation and the subsequent behaviour of the plasma have been investigated. The measured pellet penetration depth estimated on the basis of the duration of the H? emission is shallower than the depth predicted from the simple neutral gas shielding (NGS) model. It can be explained by the NGS model with inclusion of the effect of fast ions on the ablation. Just after ablation, the redistribution of the ablated pellet mass was observed on a short timescale (~400?ms). The redistribution causes shallow deposition and low fuelling efficiency.

In the large helical device (LHD) radiation profiles measured using arrays of resistive metal, foil bolometers are used to investigate the change in radiation resulting from a replacement of stainless steel divertor plates with graphite tiles between the second and third experimental campaigns. In particular, for the magnetic configuration of R axis = 3.6 m and at line averaged densities below 3 x 10 19 m 3 , a reduction of the radiated power fraction from 35% in the second campaign to down to 12% in third campaign was observed. Comparing similar shots (in terms of discharge parameters) from the second and third cycles the core (0 < r/a < 0.79) radiation fraction was reduced from 44% to 30% of the total radiation. Spectroscopic measurements show a corresponding decrease in radiation from iron. Comparing long pulse discharges the radiated power fraction reduced from greater than 67% during the density limiting oscillation observed in the second campaign to 20% during the third campaign with a reduction in the respective core radiation fractions from 63% to 37%.

Semiconductor detectors based on natural diamonds have been installed on the Large Helical Device (LHD) heliotron to measure the energy distribution of charge exchange fast neutral particles from different viewing angles. Advantages of a natural diamond detector (NDD) are (1) very compact size, (2) relatively easy handling, and (3) high energy resolution. Although NDDs are sensitive to visible light, vacuum ultraviolet, and soft x rays, unfavorable pulses produced by such radiation were greatly reduced by choosing an appropriate stainless steel shield in this experiment. In LHD, the time-resolved energy distribution of counter-going beam ions and ion cyclotron range of frequency-produced energetic ions have been successfully obtained by means of an NDD. The performance of NDDs as a neutral particle analyzer and its good suitability to LHD plasmas were demonstrated throughout this work.

Recent experimental results are summarized. One of them is the bifurcation phenomenon of the electric potential which manifests itself in various aspects of CHS plasmas. Here, electrons heated with ECH play an essential role. The CHS will be operated, after being moved to the Toki site, so as to perform complementary experiments to LHD.

A multi-pellet injector system has been developed as a fundamental fueling tool for the Large Helical Device (LHD). Since a primary goal of the LHD project is demonstration of steady-state high-temperature plasmas, highly reliable and reproducible performance is prerequisite for the LHD pellet injector. The helium Gifford-McMahon (GM) cycle cryogenic refrigerator and conventional pipe-gun mechanism have been employed along with these requirements. Since the triple point temperature of hydrogen is lower than those of isotopes; deuterium and tritium, a careful and steady temperature control is necessary in pellet formation. The amount of propellant gas has been minimized by small reservoir to reduce heat load and inflow into the plasma vacuum chamber. Both robustness and flexibility have been realized by using the programmable logic controller combined with GUI on WindowsNT. The pellet injector has demonstrated continuous hundreds of injection without any fail and has been applied for the LHD experiment successfully.

The confinement characteristics of large net-current-free plasmas heated by neutral-beam injection have been investigated in the Large Helical Device (LHD). A systematic enhancement in energy-confinement times from the scaling derived from the medium-sized heliotron/torsatron experiments have been observed, which is attributed to the edge pedestal. The core confinement is scaled with the Bohm term divided by the square root of the gyro radii. The comparative analysis using a dimensionally similar discharge in the Compact Helical System indicates gyro-Bohm dependence in the core and transport improvement in the edge region of LHD plasmas.

The initial experiments on the Large Helical Device (LHD) have extended confinement studies on currentless plasmas to a large scale (R = 3.9 m, a = 0.6 m). Heating by NBI of 3 MW produced plasmas with a fusion triple product of 8 × 1018m-3keVs at a magnetic field strength of 1.5 T. An electron temperature of 1.5 keV and an ion temperature of 1.1 keV were achieved simultaneously at a line averaged electron density of 1.5 × 1019 m-3. The maximum stored energy reached 0.22 MJ with neither unexpected confinement deterioration nor visible MHD instabilities, which corresponds to β = 0.7%. Energy confinement times reached a maximum of 0.17 s. A favourable dependence of energy confinement time on density remains in the present power density (~40 kW/m3) and electron density (3 × 1019 m-3) regimes, unlike the L mode in tokamaks. Although power degradation and significant density dependence are similar to the conditions on existing medium sized helical devices, the absolute value is enhanced by up to about 50% from the International Stellarator Scaling 95. Temperatures of both electrons and ions as high as 200 eV were observed at the outermost flux surface, which indicates a qualitative jump in performance compared with that of helical devices to date. Spontaneously generated toroidal currents indicate agreement with the physical picture of neoclassical bootstrap currents. Change of magnetic configuration due to the finite β effect was well described by 3-D MHD equilibrium analysis. A density pump-out phenomenon was observed in hydrogen discharges, which was mitigated in helium discharges with high recycling.

The effects of the plasma profile on the global energy confinement have been studied in Heliotron E with special regard to differences between heating methods (ECH, NBI and NBI + ECH). With high power NBI, peaked Ti and peaked ne profiles (Ti(0)/Ti 2.7, ne(0)/ne 4.5) were simultaneously achieved under low recycling conditions. A peaked ne profile (ne(0)/ne 2.5 ) could lead to the high Ti mode where the ion heat transport in the central region is substantially reduced. By changing the ECH launching condition (on-axis, off-axis and toroidally oblique injection), the peakedness of the Te profile could be controlled in the range 1.3 Te(0)/Te 4.5. A peaked Te profile and a flat ne profile (3.5 Te(0)/Te, ne(0)/ne 1.8) were brought about by the well focused on-axis ECH. The ECH plasma with a peaked Te profile has higher stored energy than that with a moderately peaked Te profile for the same injected ECH power and the same density region. The global energy confinement time normalized by the LHD scaling, τE G/τE LHD, showed ne(0)/ne dependence for the low Ti mode NBI plasmas. For the high Ti mode, the ne(0)/ne dependence of τE G/τE LHD was weak. These findings suggest that the LHD scaling should be modified to scale the global energy confinement of the helical plasmas in a wide range of ne(0)/ne.

Variation of the plasma position relative to the centre of the helical coil winding is a very effective means of controlling the MHD stability and the trapped particle confinement in heliotron/torsatron systems, but improving one of these two characteristics with this parameter simultaneously has a detrimental effect on the other. The inward shifted configuration is favourable for drift orbit optimization but is predicted to be unstable according to the Mercier criterion. Various physics problems, such as electric field structure, plasma rotation and MHD phenomena, have been studied in the Compact Helical System (CHS) with a compromise intermediate position. With this standard configuration, CHS has yielded experimental results that contribute to the understanding of general toroidal confinement physics and low aspect ratio helical systems. In the recent experiments, it was found that a wide range of inward shifted configurations give stable plasma discharges without any restriction to the special pressure profile. Such an enhanced range of operation made it possible to study experimentally the drift orbit optimized configuration in heliotron/torsatron systems. The effect of configuration improvement was studied with plasmas in a low collisionality regime.

The Large Helical Device (LHD) has successfully started running plasma confinement experiments after a long construction period of eight years. During the construction and machine commissioning phases, a variety of milestones were attained in fusion engineering which successfully led to the first operation, and the first plasma was ignited on 31 March 1998. Two experimental campaigns were carried out in 1998. In the first campaign, the magnetic flux mapping clearly demonstrated a nested structure of magnetic surfaces. The first plasma experiments were conducted with second harmonic 84 and 82.6 GHz ECH at a heating power input of 0.35 MW. The magnetic field was set at 1.5 T in these campaigns so as to accumulate operational experience with the superconducting coils. In the second campaign, auxiliary heating with NBI at 3 MW has been carried out. Averaged electron densities of up to 6 × 1019m-3, central temperatures ranging from 1.4 to 1.5 keV and stored energies of up to 0.22 MJ have been attained despite the fact that the impurity level has not yet been minimized. The obtained scaling of energy confinement time has been found to be consistent with the ISS95 scaling law with some enhancement.

Li pellets of large size were injected into electron cyclotron resonance (ECR) heated plasmas and neutral beam injection (NBI) heated plasmas of Heliotron E. The discharge behaviour, pellet ablation and wall conditioning were studied. The electron pressure is doubled after injection into the NBI plasma and remains unchanged in the case of ECR heating. This may be due to the energy exchange between the electrons and thermal ions with the fast ions from the neutral beam. The observed discrepancy between the experimental and modelled ablation rates may be caused by both the plasma cooling due to pellet ablatant and the ablation stimulated by the fast ions in the NBI-heated regime and by the fast electrons in the ECR-heated regime. In preliminary experiments on wall conditioning by Li pellet injection, no improvement of plasma performance after Li pellet injection was observed in the divertor or limiter configuration, with the limiter radii .

A new repetitive multibarrel pellet injector for a steady-state plasma fuelling of Iarge fusion devices has been designed. The steady-state operation is provided by ten pipe-guns with unique porous units forming solid hydrogen pellets for 5-9 s in every barrel. Over one thousand hydrogen pellets have been formed and aecelerated to 1.2 km/s at different repetition rates. The injector design and experimental results are presented.

Antiinflammatory activities of aqueous and saponin extracts and ecdysterone obtained from Pfaffia iresinoides (Sprengel) were studied by using three experimental inflammatory models in rats. The saponin extract (25 and 50 mg/kg, p.o.) reduced the leukocyte migration, particularly of mononuclear cells in the carrageenin-induced pleurisy. It also inhibited the granuloma tissue formation following cotton pellet implantation and the complete Freund's adjuvant-induced arthritis. The aqueous extract, in the same conditions, was effective on both carrageenin-induced pleurisy and complete Freund's adjuvant arthritis. However, it did not alter the granuloma formation. The ecdysterone (5 mg/kg, p.o.), isolated from P. iresinoides, showed no effect on these inflammatory processes. © 1997 John Wiley & Sons, Ltd.

A device for producing a tracer-encapsulated cryogenic pellet is constructed for an accurate transport diagnostic system to measure particle transport both parallel and perpendicular to the magnetic-field lines in magnetic confinement devices. As for the typical configuration of the tracer-encapsulated pellet, it is proposed that a 50–250 μm diam tracer made of a light atom such as lithium, carbon, etc., is encapsulated in the center of a 1–3 mm diam cylindrical pellet of hydrogen. For demonstration of the device operation, a 240 μm diam carbon sphere is encapsulated in the center of a 3 mm diam cylindrical pellet of hydrogen, and accelerated by a light gas gun to velocities of 400–800 m/s in a test chamber. The pellet has been photographed simultaneously from two directions and the two two-dimensional images are reconstructed to a three-dimensional image. Thus, the proof of principle of the device operation has been demonstrated.

A kinetic study was done on the decomposition of source materials used in metalorganic vapor phase epitaxy (MOVPE) such as trimethylgallium, trimethylindium, tertiarybutylarsine, tertiarybutylphosphine and dimethylzinc. The purpose of this study was to construct reaction models with accurate rate constants, which are required for the numerical analysis of MOVPE process and computer assisted process optimization. For the measurements we employed a quartz-tube cracking reactor and Fourier transform infrared spectrometer (FT-IR) as the gas monitoring system. First, the decomposition rate of each source was measured and the ability of the system to determine source gas decomposition rates was validated. Next the effect of substrate surfaces on the decomposition rates and the effect of gas mixing were examined. We observed that surface reaction rates were not negligible in the decomposition of some sources, and that the decomposition rates of group III sources increased when they were mixed with group V sources. The results of this study showed that the effect of substrates and gas mixing need to be properly accounted for in numerical models to accurately simulate epitaxial growth process.

1. 1. The absorption of piroxicam into the blood of rats is significantly slower after oral administration of piroxicam β-cyclodextrin than of free piroxicam. 2. 2. The pharmacokinetic profiles of piroxicam in rat lymph were very similar in both groups. 3. 3. Bioavailability of piroxicam in plasma is higher after treatment with the inclusion product than with free piroxicam. On the other hand, bioavailability in lymph is higher when free piroxicam is administered.

Preliminary plans for two-dimensional steady state bolometric measurements of core plasma and divertor regions have been made for the Large Helical Device (LHD) under construction at the National Institute for Fusion Science. Using a semi-tangential plane through the plasma volume, a two-dimensional view of the core plasma is achieved from the outboard, upper and lower diagnostic ports. Divertor regions will also be viewed from the upper, lower and outboard ports. In the case of divertor and core plasma arrays, duplicate detector arrays will alternate in turn between viewing and active cooling phases, using fast shutters to enable continuous detection during long-pulse (30 min) operation of the LHD. Each detector array will consist of 32 metal film bolometers and 64 XUV photodiode arrays, resulting in a spatial resolution of about 2–4 cm. The temporal resolution should be about 1 ms for the film bolometers and 1 μs for the photodiodes. Additional arrays will include a one-dimensional array that views from an outboard port, and an array of toroidally spaced detectors for investigating the toroidal variation of the radiated power. During the present stage of development, various detector samples are being acquired and tested. Schematics of the bolometer arrays, as well as plans for the complete bolometer diagnostic system will be shown.

An innovative device for producing a double-layer pellet was designed, constructed and operated for the purpose of establishing an accurate transport diagnostic system to measure particle transport both parallel and perpendicular to the magnetic field lines of magnetic confinement devices. For the precise set-up of the cryohead, special techniques were used, and the wholw device was successfully constructed. The production of a double-layer pellet was demonstrated, and its image of double-layer configuration was photographed during flight in both vertical and horizontal directions, taken by fast flash lamps. Thus, proof-of-principle of the production method of a double-layer pellet for the diagnostics purposes is demonstrated for the first time.

A pellet injector of the repeating pneumatic pipe-gun type has been designed for plasma fueling applications. Its use reduces the time for pellet formation by an in situ technique from 2 to 3 min to 2–10 s. The basic idea of the proposed approach to pellet formation is to melt prefrozen solid fuel and to admit it through a porous unit into a barrel for refreezing. The injector provides for a continuous injection of an unlimited number of pellets. Over 250 hydrogen and deuterium pellets of 3 mm diameter and 3–10 mm in length were accelerated to 1.2 km/s at a rate of 1 pellet per 10–34 s by manually controlled injector operation. An automatically controlled multishot pellet injector (>10 barrels) is capable of providing a continuous and reliable fueling of large fusion devices such as the large helical device and the International Thermonuclear Experimental Reactor (ITER).

The Heliotron E device is characterized by a large aspect ratio, , large rotational transform, and , high shear, , an and M = 19 helical coil, two vertical field coils and 19 toroidal coils (19 toroidal coils were removed to increase neutral beam injection (NBI) heating power up to 4 MW in 1985), where is the rotational transform, is the average minor radius, R is the major radius, is the pole number and M is the helical period number of the magnetic field. Theoretical characteristics of Heliotron E are summarized in section 2. Initial experiments in 1980 - 3 were mainly for studying ohmically heated plasmas. Topics relating to current-carrying plasmas are reviewed in section 3. In Heliotron E the first currentless plasma was produced by ECRH using a gyrotron with a frequency of 28 GHz in 1982. Then the gyrotron frequency was increased to 53 GHz to produce higher density currentless plasmas. After NBI heating of the target plasma produced by ECRH was successful, currentless plasmas were studied intensively in Heliotron E. In section 4, the production and heating of currentless plasmas by ECRH, NBI and ion cyclotron range of frequency (ICRF) are summarized. MHD properties of currentless Heliotron E plasmas are summarized in section 5. Confinement and transport are discussed for ECRH, NBI and ICRF plasmas in section 6. Characteristics of edge plasma and plasma - wall interaction in Heliotron E are summarized in section 7. Configuration improvement and future directions based on Heliotron E results are discussed in section 8.

Radially resolved measurements of the plasma ion distribution function by detecting charge exchange neutrals from an impurity pellet ablation cloud require a fast operating energy analyzer working at high count rates to build several spectra during the pellet flight. Currently a solid state detector in the pulse height analysis (PHA) mode is used for such measurements on the Large Helical Device. Traditional PHA techniques cannot provide the operating speed required for a good spatial resolution. An algorithm has been proposed based on digital processing of noisy data series containing charge-sensitive preamplifier signals with discontinuities corresponding to incident particles. The algorithm employs the modified Tikhonov regularization and the successive detection–estimation of signal increments at discontinuity points. Such an approach allows one to realize an ultrafast particle energy spectroscopy by taking advantage of detector/preamplifier capabilities without limiting the system throughput by subsequent electronics.

Spectrally narrow, pulsed outputs consisting of almost a single mode have been obtained from an optically-pumped high-power (200kW) D2O laser by adopting the injection seeding method, where single-mode radiation (seed pulse) from a low-power, compact D2O laser has been injected into the main D2O laser. Spectrally narrow outputs with high power having spectral widths as narrow as 5 MHz have been obtained, when the seed pulses with frequency tuned to one longitudinal mode of the main D2O laser have been injected at a time sufficiently before the lasing of the main laser took place. The experimental results have been compared with those of numerical simulation modified to include the injection field with varying injection times.

1. The effectiveness of the inclusion product of piroxicam with beta-cyclodextrin was compared to that of free piroxicam on inflammatory reactions by using three experimental inflammatory models in rats. 2. The inclusion compound showed anti-inflammatory effects similar to those of simple piroxicam on granuloma tissue formation and arthritis induced by complete Freund adjuvant. 3. In carrageenin-induced pleurisy, the piroxicam beta-cyclodextrin reduced leukocyte mobilization more intensely than non-complexed piroxicam. 4. These results suggest that beta-cyclodextrin is a useful tool for improving the efficacy of piroxicam.

Ignition characteristics in the D-T high field helical reactor of R=20 m, a=2 m are analyzed by the `operation path method` on the P{sub ht}{tau}{sub E}{sup 2}-T plane and `POPCON`. Based on the LHD scaling law, the strong magnetic field B{sub o}=12 to nearly 15 T makes a reactor operable with a low confinement enhancement, leading to the low helium ash accumulation. POPCON analyses with the synchrotron radiation losses, the density limit and confinement time saturation effect show that marginal confinement factors to have the fusion power of 3 GW are 0.9 to 1.3 for B{sub o}=15 T, and 1.1 to 1.6 for 12T, respectively. 11 refs., 5 figs.

Recent results of Heliotron E experiment are reviewed. Detailed studies of the plasma transport have been achieved in Heliotron E, in which the plasma wall interaction has been changed using the ECH boronization technique. The boronization realized low-density, high-T{sub i} plasmas whose ion collisionality deeply estended to the 1/{nu}{sub i}** regime. The local electron and ion thermal diffusivities in the NBI plasma are analyzed and discussed by comparison with theory-based transport models. The particle transport in ECH plasmas is investigated with edge fluctuation measurements. Both electrostatic and magnetic fluctuations are well correlated with the global particle confinement. Characteristic structures of the electric field or potential distribution are observed during the particle confinement degradation phase. It is considered that dc convective flow across the last closed flux surface is caused by the potential structure. Edge plasma flows have been discussed in connection with these studies and with asymmetric divertor heat/particle load. 10 refs., 9 figs.

Spectrally narrow outputs of about 10 MHz (full width at half‐maximum) are obtained from an optically pumped high‐power (100 kW) D2O laser system by using the oscillator‐amplifier configuration, in which a low‐power single‐mode output from a compact D2O laser with a short cavity length is amplified by a large D2O laser amplifier. In order to obtain spectrally narrow outputs from the amplifier, the following three conditions need to be satisfied: (1) the D2O gas pressure of the amplifier is adjusted in the range from 4 to 6 Torr; (2) the oscillation frequency of the compact laser is tuned in the range about 15–35 MHz lower than the Raman resonance frequency; and (3) the intensity of the compact laser beam injected into the amplifier is larger than about 50 W/cm2.

The spectra of the stimulated Raman emission from D 2 O vapor optically-pumped by a pulsed CO 2 laser were measured with a heterodyne receiver having a high frequency resolution of 1.3 MHz. The measurements were carried out for two D 2 O Raman cells of 4.3 m and 0.3 m length, and for various gas pressures. For gas pressures higher than 4 Torr, the measured spectra had a width of a few tens of megahertz and peaked around the Raman resonance frequency for both the two Raman cells. For gas pressures lower than 2 Torr, slightly different spectral characteristics were observed between the 4.3 m and 0.3 m cells. A brief discussion is given referring to the existing theory.

A new electron cyclotron heating (ECH) system has been installed on the Heliotron-E helical device. The gyrotron output 106 GHz TE 12,2 mode is converted into a gaussian beam by the quasi-optical Vlasov convertor. The gaussian beam is coupled to the HE 11 waveguide mode, then transmitted by the corrugated waveguides. The transmitted beam is well focused and launched to the Heliotron-E device. Plasma has been produced and heated by this 106 GHz ECH. The second harmonic breakdown was investigated and compared with the fundamental harmonic breakdown. The improvement of the particle confinement was observed during 106 GHz second harmonic ECH. Compared with the 53 GHz fundamental ECH phase, the averaged electron density was increased by 20% without gas puffing. The outflux to the divertor plate was reduced.

We have measured extreme ultraviolet (EUV) spectra in the 20 nm region from tungsten ions in plasmas produced in the Large Helical Device (LHD) at the National Institute for Fusion Science. The spectra are recorded by a grazing incidence spectrometer following an injection of a tungsten pellet. A quasicontinuum feature has been observed in the 20 nm range under low temperature conditions below 1.0 keV, where large contributions of charged states lower than W27+ are expected. In order to give an insight into this spectral feature, we have carried out atomic structure calculations for W7+-W27+ using Cowan's code. The calculated distributions of wavelengths and gA values suggest that the emission largely arises from n = 5-5 transitions in stages lower than W27+.

We developed a micro-area X-ray diffraction system using a sub-µm X-ray beam of 10 keV energy that was produced by a phase zone plate made of tantalum. Using this system, we were able to measure the lattice strain distribution in InGaAsP metalorganic vapor phase epitaxial layers selectively grown on InP stripe regions a few µm in width between a pair of SiO2 mask stripes, with strain sensitivity of about 1×10-4. We found that the strain distribution in a 3-µm-wide stripe layer is almost completely uniform, while that in a 4-µm-wide layer is not.

Extreme ultra‐violet (EUV) emission spectra from highly charged tin, xenon and tungsten ions have been measured in optically thin high‐temperature plasmas produced in the Large Helical Device (LHD) at the National Institute for Fusion Science by using a grazing incidence spectrometer and a tracer‐encapsulated solid pellet (TESPEL) injector. Quasi‐continuous spectral features arising from unresolved transition array (UTA) of open 4d subshell ions were observed for tin, xenon and tungsten around 13.5, 11, and 5 nm, respectively, when edge plasma was cooled sufficiently. The spectral appearance obviously depends on edge electron temperature and atomic number. In the case of intermediate edge temperature, sharp discrete lines from highly charged open 4s or 4p subshell ions are clearly observed for tin and xenon in the longer wavelength side of the UTAs but not the case for tungsten. Assignments of the strong discrete lines have been performed by comparison with other experimental data and the theoretical calculations generated using the Cowan code. In order to interpret the tungsten spectra it was necessary to include the contribution of open 4f subshell ions.

This study was designed to elucidate physiological changes of skeletal muscle mitochondria from broiler chickens (Gallus gallus) during chronic heat exposure. Chickens (19-day-old) were exposed to either constant heat stress (34 degrees C) or kept at control temperature (24 degrees C) for 14days. Mitochondrial ROS production for control group showed little changes during the experimental periods, whereas that for the heat-stressed group was increased after 3, 5 and 9days of heat exposure and returned to original levels at day 14. Mitochondrial membrane potential in state 4 for heat-stressed birds was higher than those of control birds after 3 and 5days, but was not at day 14. Mitochondrial oxygen consumption rate in state 3 was increased after 3 and 5days, and also returned to original levels by day 14. These results suggest that chronic heat stress induces increased ROS production in skeletal muscle mitochondria, probably via elevation of the membrane potential in state 4, resulting from enhanced oxygen consumption in the initial stage of heat exposure. These physiological changes were no longer observed at day 14, possibly because the animals had acclimatized to environmental heat stress.

The authors present a neutral gas shielding model including the distribution function of particles carrying the heat for ablation. In an ohmically heated tokamak, high energy electrons in the tail part of the Maxwellian with E approximately=6-8 Te contribute significantly to the ablation process at the pellet surface. A simple scaling for the pellet ablation rate is given which takes into account the Maxwellian electron energy distribution. The pellet penetration depth obtained with the model presented agrees well with the multigroup approximation for an energy distribution during ablation by Houlberg et al. (1988). Pellet ablation dominated by hot ions was obtained in a special NBI heated Heliotron E plasma with an electron temperature much lower than the ion temperature

A comparative study on edge plasma properties between the original “natural” divertor configuration and the material limiter configuration was performed for Heliotron E currentless plasma. By insertion of a carbon rail limiter, the particle and heat fluxes to the divertor footprint were reduced to 20–50% of that in the divertor configuration. Such a reduction of influx resulted in the decrease of metal impurities sputtered from the wall surface. There were no clear differences in the edge density and heat flux profiles for NBI plasma between the limiter and divertor scrape-off. In the limiter configuration, a highly heat loaded area was observed locally on only one side of the limiter head. A perturbation field affected this local heat load.

The reduction of metallic impurity was found in a carbon limiter configuration in Heliotron E. In order to investigate the impurity penetration into the plasma, the distance between the outermost magnetic surface and the vacuum vessel wall was varied by inserting a carbon rail limiter. The analysis of vacuum ultraviolet impurity spectra and charge exchange neutral fluxes shows that the decrease of the impurity production rates by charge exchange neutral particles is the most probable reason to explain the experimental results. Moreover the electron temperature and density profiles in the limiter shadow provide an ability to screen metallic impurity influxes from the wall.

Properties concerning the metal-insulator transition (MIT) in the NiS 2− x Se x system were studied on polycrystalline samples with x ⩽ 0.73 by susceptibility (χ), neutron diffraction, electrical resistivity (ϱ) and specific heat measurements. It is confirmed that a first-order MIT occurs below the Neel temperature with increasing temperature for x ≈ 0.5. The critical points is located around ( x cr , T cr ) = (0.6, 125 K). When x or T is varied across the MIT, although χ and ϱ are discontinuous, the magnetic moment contributing to the antiferromagnetic order is continuous. The effect of strong electron correlation appears in various quantities in the metallic state at x ≈ 0.5: large values of χ (4.2 K) and a linear electronic specific heat coefficient, and a T 3 ln T term in the specific heat. When Ni is substituted by Co, Cu or Co+Cu at x ≈ 0.5, the MIT temperature varies similarly.

Frequency stabilization of a 1.55 mu m DFB laser diode is demonstrated using vibrational-rotational absorption of /sup 12/C/sub 2/H/sub 2/ and /sup 13/C/sub 2/H/sub 2/ molecules (named VRAM). Frequency stability within 2 MHz peak to peak fluctuation can be achieved in the wavelength region of 1.51-1.55 mu m. Frequency-stabilized DFB laser compact modules have been constructed. Frequency stabilities are evaluated by measuring the beat spectrum of the two lasers. In addition, the temperature and pressure dependences of the acetylene absorption lines are characterized. >