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Recent R&D of an edge Thomson scattering system for ITER (International Thermonuclear Experimental Reactor) are reviewed. We have designed a diagnostic laser system (5 J, 100 Hz) based on JT-60U diagnostic laser design (7.46J, 50Hz). New laser oscillator has been developed, and prototype amplifier has been assembled for ITER. Regarding a collection optics in a port plug, improvement of previous design has been carrying out. As for spectrometers, a new technique of Fourier transform spectrometer for Thomson scattering has been considered in addition to a filter polychromator.

In JFT-2M, the applicability of reduced activation ferritic steel to a fusion demonstration reactor has been demonstrated mainly concerning the ferromagnetic effect on plasma production, control, stability and confinement. The compatibility of the close ferritic wall with high-normalized beta plasmas has been investigated mainly because the demonstration reactor will utilize the wall stabilization effect. Due to improvements in the operation scenario and the modification of the guard limiter configuration, the region showing good compatibility was extended to the closer wall position (the wall position was normalized to the plasma minor radius; rwall/a~ 1.25) and the higher normalized beta (?N~ 3.5), compared with the previous works with the relatively far wall position and stronger magnetic field (Tsuzuki K. et al2003 Nucl. Fusion. 431288). A reduction in the growth rate of the instability was also observed in the close wall case, which presumably corresponds to the wall stabilization effect, similar to a resistive wall without ferromagnetism.

Confinement degradation of energetic ions due to Alfvén eigenmodes (AEs) has been investigated with negative ion based neutral beam injection at ~370?keV into JT-60U weak shear plasmas. AEs with a rapid frequency sweeping and then saturation as the minimum value of the safety factor decreases have been observed. This frequency behaviour can be explained by the reversed-shear induced AE (RSAE) and the transition from RSAEs to the toroidicity-induced AEs (TAEs). The associated change in the charge exchange neutral particle flux suggests energetic ion transport due to these AEs. The total neutron emission reduction rate in the presence of these AEs is evaluated by calculation using the orbit following Monte-Carlo code taking into account the change in bulk plasmas. The evaluation indicates confinement of energetic ions is degraded due to these AEs. In particular, it is found that the confinement degradation of energetic ions is maximum during the transition from RSAEs to TAEs and the maximum reduction rate (?Sn/Sn)MAXis estimated to be ~45%.

Two types of small-poloidal wavelength low frequency floating potential fluctuations (~1?kHz, and 10-15?kHz) are observed in the edge region of ohmically heated plasmas in the JFT-2M tokamak. The higher frequency fluctuations are inferred as geodesic acoustic modes (GAMs). Significant bicoherences between both modes and the broad-band fluctuations are observed simultaneously; however, frequency ranges are different. A significant bicoherence range is from 70 to 125?kHz at the lower frequency modes (LFM) and is from 20 to 125?kHz at the GAM. Phase angles at the significant bicoherences are coherent around ?. These results indicate that both modes are nonlinearly coupled to the broad-band fluctuations. Two spectral peaks are observed around the GAM frequency and the difference in peak frequencies is around the LFM frequency, suggesting nonlinear couplings between the LFM and the GAM. However, the modulation of the GAM by the LFM is not conclusive. In this paper, the results of the letter (Nagashima et al2005 Phys. Rev. Lett.95095002) are presented in detail.

The electrostatic and density fluctuation are measured simultaneously with a heavy ion beam probe. The electrostatic fluctuation with the geodesic acoustic mode (GAM) frequency is observed in L-mode plasmas and not in H-mode plasmas. The poloidal and radial structure is consistent with the GAM. So the fluctuation is concluded to be the GAM.

The characteristics of geodesic–acoustic-mode (GAM) are investigated through direct and simultaneous measurement of electrostatic and density fluctuations with a heavy ion beam probe.The amplitude of the GAM changes in relation to the radial position; it is small near the separatrix, reaches a local maximum at 3 cm inside the separatrix and then decreases again to 5 cm inside the separatrix. The frequency is constant in the range, though the predicted GAM frequency varies according to the temperature gradient. The correlation length is about 6 cm and comparable to the structure of the amplitude of the GAM. The results indicate the GAM has a radial structure which reflects the local condition at about 3 m inside the separatrix.The phase relation between the GAM oscillation indicates that the GAM is a radial propagating wave.The interaction between the GAM and the ambient density fluctuation is shown by the high coherence between the GAM oscillation and the temporal behaviour of the ambient density fluctuation. Moreover, the phase relation between the electric field fluctuation of the GAM ( ) and the amplitude of the density fluctuation indicates that the modulation of the ambient density fluctuation delays the . The causality between the GAM and the modulation of the density fluctuation is revealed.

The characteristics of geodesic-acoustic-mode (GAM) are investigated through direct and simultaneous measurement of electrostatic and density fluctuations with a heavy ion beam probe.

This paper presents results of bispectral analysis applied to floating potential fluctuations in the edge region of ohmically heated plasmas in the JAERI Fusion Torus-2 Modified (JFT-2M) tokamak. Inside the outermost surface of plasmas, coherent mode fluctuations (CMs) in floating potential were observed around the frequency of the geodesic acoustic mode. The squared bicoherence shows significant nonlinear couplings between the CMs and background fluctuations. The biphase at the frequency of the CMs is localized around ?, while that at frequencies of background fluctuations distributes in a wide range. The total bicoherence at the frequency of the CMs is proportional to the squared amplitude of the CMs. These observations are consistent with the theoretical prediction on the drift wave-zonal flow systems. Interpretation of the absolute value of the total bicoherence is also discussed.

A key feature of the 'high recycling steady' (HRS) H-mode regimes is the reduction of the transient heat load to the divertor target due to large ELMs. The heat flux to the divertor targets measured by means of a Langmuir probe in the scrape-off layer on the target plate is about ~0.3?MW?m?2in the typical HRS plasmas, which is very small in comparison with the transient heat load in the ELMy H-mode discharge. In addition, the effects of the plasma shaping on the access to and improved plasma performance of HRS H-mode regimes have been investigated. Furthermore, simultaneous measurements of both density fluctuations and potential profiles at the plasma edge region using a heavy ion beam probe are also presented.

AbstractThe diagnostic system of JFT-2M has consisted of about 30 individual diagnostic instruments, which were used to study plasma production, control, equilibrium, stability, confinement, plasma heating by neutral beam injection and/or by radio-frequency (rf) (lower hybrid, ion cyclotron resonance frequency, electron cyclotron heating), and current drive by rf. In these instruments, the motional Stark effect polarimeter, charge-exchange recombination spectroscopy, heavy ion beam probe, time-of-flight neutral particle analyzer, etc., have helped in further understanding the improved mechanism of confinement such as H-mode and high-recycling-steady H-mode, and operational regimes of these modes. An infrared television camera system and a lost ion probe have played a very important role in investigating the heat load on the walls due to ripple lost particles and escaping ions from the core plasma region, respectively.

AbstractA compact toroid (CT) injector is considered to comprise one of the advanced refueling methods for the fusion reactor. In JFT-2M, it was demonstrated for the first time that a CT injected into a neutral beam-heated plasma penetrated deeply into the plasma and caused a rapid increase in the electron density. We also observed interesting motions such as shift and reflection of the injected CT plasma as well as magnetic fluctuations induced just after CT injection. A power spectrum analysis suggested that this fluctuation was related to magnetic reconnection between the CT plasmoid and the toroidal field. We also modified the shape of the CT injector electrodes to improve CT injection efficiency. As a result, the CT parameters were superior to those of previous experiments, and the operational window became broader. Finally, it has been successfully demonstrated that a CT could be transported smoothly through curved drift tubes, which is one of the key technologies to avoid adverse effects of the toroidal field and to extend flexibility of the design and layout of the CT injector to access larger devices.

AbstractCompatibility between plasma and reduced activation ferritic steel, which is the leading candidate for the structural material of a fusion demonstration reactor, has been investigated in the Advanced Material Tokamak EXperiment (AMTEX). Ferritic plates (FPs) were installed progressively in the JFT-2M tokamak. The effect of ferromagnetism on plasma production, control, confinement, and stability has been investigated. Impurity release behavior has also been investigated. Even when the inside vacuum vessel wall was fully covered with the FPs and the tokamak plasma was operated close to the wall, no deleterious effect was observed, and the normalized beta could be increased up to ~3.5. Thus, encouraging results are obtained for application of this material to the demonstration reactor.

AbstractExperimental efforts on JFT-2M have been devoted to understanding the scrape-off-layer (SOL)/divertor plasmas and to investigating power and particle control by boundary plasma modification. Starting in 1985, an open divertor configuration was adopted for the first decade of the JFT-2M experiments. The characteristics of SOL/divertor plasmas such as in/out asymmetry for divertor plasmas, heat and particle diffusivities, and SOL current during an edge-localized-mode event were identified. The power and particle flux was successfully handled by active control methods such as local pumping, boundary plasma ergodization, divertor biasing, electron cyclotron wave edge heating, and fueling optimization. In 1995, to improve the power and particle control capability of the divertor, the JFT-2M divertor was modified to have a closed configuration, which demonstrated the baffling effects with its narrower divertor throat. A dense and cold divertor state (nediv= 4 × 1019m-3and Tediv= 4 eV), compatible with improved confinement modes (e.g., H-mode), was realized with strong gas puffing in a closed configuration. Edge plasma fluctuations related to the H-mode physics were identified by an electrostatic probe and magnetic measurements. These are reviewed in this paper.

AbstractIn JFT-2M, the toroidal magnetic field (TF) ripple was reduced by ferritic insert. Two kinds of ripple reduction were carried out. In the first case, ferritic steel was installed between the TF coil (TFC) and the vacuum vessel, just under the TFCs outside the vacuum vessel. In the second one, ferritic steel was installed inside the vacuum vessel covering almost the whole inside wall. The ripple was successfully reduced in both cases. The temperature increment on the first wall, which indicates the ripple-induced loss of fast ions, was measured by infrared television and was also reduced. The effect of the localized larger ripple was also investigated by attaching additional ferritic steel. A new version of the orbit-following Monte Carlo (OFMC) code was developed including the three-dimensional complex structure of the TF ripple and the nonaxisymmetric first-wall geometry. The experimental results and the new OFMC calculation were consistent.

AbstractThe experimental program on the JFT-2M tokamak started with the first plasma on April 27, 1983, and was completed in March 2004. In the series of experiments for 21 yr, many significant results in fusion energy research and plasma physics have been produced. As the first paper of this special issue on JFT-2M, this paper provides an overview of the JFT-2M program.

To investigate energetic ion transport induced by bursting modes in the frequency range of Alfvén eigenmodes, which is called abrupt large-amplitude events (ALEs) driven by negative-ion-based neutral beam (N-NB) injection, neutron emission profile measurement and charge exchange (CX) neutral particle (flux) measurement using a natural diamond detector have been performed simultaneously in JT-60U. It is found from the CX neutral particle (flux) measurement that energetic neutral particles in a limited energy range (100–370 keV) are enhanced due to ALEs, and the neutron radial profile is flattened. The change in the energetic ion density profile inferred from these measurements indicates that ALEs expel energetic ions from the core region of the plasma and induce both redistribution and loss of energetic ions. It has been shown that the energy range of transported energetic ions is consistent with a resonance condition between energetic ions and ALEs, and the energetic ion transport results from the resonant interaction between energetic ions and ALEs. Further, a fraction of the energetic ion loss has been quantitatively estimated to be ∼4%.

Results of coherent edge fluctuation measurements using three diagnostics (a reciprocating Langmuir probe, a two channel O-mode reflectometer, and fast magnetic probes) in H-mode discharges on JFT-2M are presented. In discharges in which a high recycling steady (HRS) H-mode phase is obtained through a transient phase with slightly enhanced D_α intensity, two types of coherent fluctuations are observed. The higher frequency mode (around 300 kHz) is the high frequency mode (HFM) observed in the HRS H-mode (Kamiya K et al 2003 9th IAEA Tech. Meeting H-mode Workshop Topic B-14). The lower frequency mode has a frequency of around 80 kHz. The HFM is detected by a Langmuir probe over a wide region in the SOL, as well as by the reflectometer and magnetic probes. However, the HFM is not detected by the higher frequency (38 GHz) channel of the reflectometer after the HRS transition, suggesting that the HFM is not located deeply inside the plasma. The 80 kHz mode is detected by both channels of the reflectometer and by a Langmuir probe, but not by magnetic probes, suggesting that it is an electrostatic mode. In contrast to the HFM, the 80 kHz mode is detected by the Langmuir probe only near the separatrix during the transient phase, which leads to either the HRS phase or the ELMy phase, and is similar to the fluctuations reported in Shinohara K et al (1998 J. Plasma Fusion Res. 74 607).

A new operating regime, ‘high recycling steady’ (HRS) H-mode regime, has been discovered in the JFT-2M tokamak. It is easily reproduced with neutral beam heating of any co-, balanced-, or counter-injection under wall fuelling from the boronized first wall. The HRS is characterized by good energy confinement (H_89P ~ 1.6) at a high density (n_e/n_GW ~ 0.7; n_GW is the Greenwald density), low radiation loss power fraction ( _NH_89P ~ 6 at n_e/n_GW ~ 0.7–1.0, transiently.

Compatibility between the plasma and low activation ferritic steel, which is a candidate material for fusion demonstration reactors, has been investigated step by step in the JFT-2M tokamak. We have entered the third stage of the Advanced Material Tokamak EXperiment (AMTEX), where the inside of the vacuum vessel wall is completely covered with ferritic steel plates ferritic inside wall (FIW). The effects of a FIW on the plasma production, impurity release, the operation region, and H-mode characteristics have been investigated. No negative effect has been observed up to now. A high normalized beta plasma of β_N ~ 3, having both an internal transport barrier and a steady H-mode edge was obtained. A remarkable reduction in ripple trapped loss from 0.26 MW m⁻² (without ferritic steel) to less than 0.01 MW m⁻² was demonstrated by the optimization of the thickness profile of FIW. A code to calculate fast ion losses, taking into account the full three-dimensional magnetic structure was developed, and values obtained using the code showed good agreement with experimental results. Thus, encouraging results are obtained for the use of this material in the demo-reactor.

The diagnostic system of JT-60U (JT-60upgrade) is composed of about 50 individual diagnostic devices. Recently, the detailed radial profile measurements of plasma parameters have been improved, so that the internal structure of plasmas could be explored. The understanding of plasma confinement has been enhanced by density and temperature fluctuation measurements using a mm-wave reflectometer and electron cyclotron emission measurements, respectively. In addition, real-time control experiments of electron density, neutron yield, radiated power, and electron temperature gradient have been carried out successfully by corresponding diagnostic devices. These measurements and the real-time control contribute to improving plasma performance. Diagnostic devices for next generation fusion devices such as a CO2laser interferometer/polarimeter and a CO2laser collective Thomson scattering system have been developed.

Energetic particle experiments in JT-60U are summarized, mainly covering ripple loss and Alfvén eigenmodes (AE modes). Significant loss was observed for 85 keV neutral beam injected (NBI) ions and fusion-produced tritons as toroidal field ripple at the plasma surface increased, especially in a reversed shear plasma. Measurement of hot spots on the first wall due to ripple loss confirmed agreement with code predictions, validating the modeling incorporated in an orbit-following Monte Carlo code. A variety of AE modes were destabilized in ion cyclotron range of frequencies (ICRF) minority heating and negative-ion-based NBI (N-NBI) heating. Most of the observed modes are gap modes identified to be toroidicity-induced, ellipticity-induced, and triangularity-induced AE modes. An interesting finding is pulsating modes accompanying frequency sweep, which were destabilized by N-NBI and sometimes induced a beam ion loss of up to 25%. Also presented are energetic particle issues in auxiliary heating with ICRF and N-NBI.

Fusion plasma performance and confinement studies on JT-60 and JT-60U are reviewed. With the main aim of providing a physics basis for ITER and the steady-state tokamak reactors, JT-60/JT-60U has been developing and optimizing the operational concepts, and extending the discharge regimes toward sustainment of high integrated performance in the reactor relevant parameter regime. In addition to achievement of high fusion plasma performances such as the equivalent breakeven condition (QDTequp to 1.25) and a high fusion triple product nD(0)τETi(0) = 1.5 × 1021m-3skeV, JT-60U has demonstrated the integrated performance of high confinement, high βN, full non-inductive current drive with a large fraction of bootstrap current. These favorable performances have been achieved in the two advanced operation regimes, the reversed magnetic shear (RS) and the weak magnetic shear (high-βp) ELMy H modes characterized by both internal transport barriers (ITB) and edge transport barriers (ETB). The key factors in optimizing these plasmas towards high integrated performance are control of profiles of current, pressure, rotation, etc. utilizing a variety of heating, current drive, torque input, and particle control capabilities and high triangularity operation. As represented by discovery of ITBs (density ITB in the central pellet mode, ion temperature ITB in the high-βpmode, and electron temperature ITB in the reversed shear mode), confinement studies in JT-60/JT-60U have been emphasizing freedom and also restriction of radial profiles of temperature and density. In addition to characterization of confinement and analyses of transport properties of the OH, the L-mode, the H-mode, the pellet mode, the high-βpmode, and the RS mode, JT-60U has clarified formation conditions, spatial structures and dynamics of edge and internal transport barriers, and evaluated effects of repetitive MHD events on confinement such as sawteeth and ELMs. Through these studies, JT-60U has demonstrated applicability of the high confinement modes to ITER and the steady-state tokamak reactors.

Bursting modes in the frequency range of the toroidicity induced Alfvén eigenmode are observed in the plasma to which the negative-ion-based neutral beam (N-NB) is injected. A bursting mode changes its frequency by 10-20 kHz in 1-5 ms and is called fast frequency sweeping (fast FS) mode. Another bursting mode evolves explosively in ≤400 µs and is called an abrupt large-amplitude event. The dependence of their saturation level was compared with the experimentally observed growth rate and damping rate. The mode amplitude increases with the observed growth rate for fast FS modes. The modes with large amplitude and a large enhanced transport were observed when a large neutron emission rate was observed. The burst period increases as the drop ratio of the neutron emission increases.

The seco-Cl 3-methoxycarbonyl-2-trifluoromethylcyclopropapyrroloindole (MCTFCPI) derivatives dl- and/or (S)-10 carrying various acyl moieties at the N6-position were synthesized along with their prodrugs (S)-12, and their antitumor activity was evaluated. Among these derivatives, AT-3510 [(S)-12m], the novel prodrug MCTFCPI derivative carrying a 5-(7-methoxybenzofuran-2-ylcarbonyl)aminoindole-2-carbonyl group at the N6-position, was found to exhibit more excellent antitumor activity against human tumor xenografts than the clinical trial candidates carzelesin (6) and KW-2189 (7) and cisplatin.

The excitation and stabilization of Alfvén eigenmodes and their impact on energetic ion confinement were investigated with negative ion based neutral beam injection at 330-360 keV into weak or reversed magnetic shear plasmas on JT-60U. Toroidicity induced Alfvén eigenmodes (TAEs) were observed in weak shear plasmas with ⟨β_h⟩ ≥ 0.1% and 0.4 ≤ v_b||/v_A ≤ 1. The stability of TAEs is consistent with predictions by the NOVA-K code. New burst modes and chirping modes were observed in the higher β regime of ⟨β_h⟩ ≥ 0.2%. The effect of TAEs, burst modes and chirping modes on fast ion confinement has been found to be small so far. It was found that a strongly reversed shear plasma with internal transport barrier suppresses AEs.

The effect of up-down asymmetric toroidal field ripple on fast ion loss was investigated experimentally in JT-60U deuterium discharges. The experiment was carried out for neutral beam (NB) injected fast ions and tritons from the d(d,p)t reaction. The loss of the NB injected fast ions was estimated from the decay of 2.5 MeV neutrons following a short pulse D⁰ beam injection of 30 ms, and the triton loss was investigated from the decay of 14 MeV neutrons following 25 MW neutral beam injection (NBI) with a duration of 2 s. It was found that up-down asymmetric ripple did not enhance the NB injected ion loss compared with the ion loss in up-down symmetric ripple. The effect of the ion Del B drift direction on the beam ion and triton losses was studied in up-down asymmetric ripple. No significant difference was observed in the loss for energetic ions between upward and downward Del B drift discharges. The loss fraction of NB injected ions predicted by an orbit following Monte Carlo code agrees with the experimental fraction

To clarify the pathophysiologic role of fibroblast growth factors in idiopathic cardiomyopathy, we evaluated endomyocardial biopsy specimens obtained from 24 patients (nine with hypertrophic cardiomyopathy [HCM], 12 with dilated cardiomyopathy [DCM], and three with hypertensive hypertrophy) and six controls. All the specimens were stained for acidic fibroblast growth factor (aFGF) and basic FGF (bFGF) with immunohistochemistry. In situ hybridization was carried out for detection of aFGF mRNA. The average diameter of the myocytes, the percent area of interstitial fibrosis, and capillary vessel density were assessed in each biopsy specimen with morphometric methods. Positive staining of aFGF was observed in the myocytes of the biopsy specimens taken from 15 of 21 (71%) patients with cardiomyopathy (six of nine HCM, nine of 12 DCM) and all hypertensive hypertrophy patients but in none of the controls (p < 0.01). The average diameter of the myocytes was significantly larger in the patients with positive aFGF staining than in those with negative staining (23.1 +/- 1.5 versus 18.3 +/- 1.2 @mm, p < 0.05). The percent area of fibrosis and the density of capillaries did not differ between the two groups. Intense expression of aFGF mRNA was observed in the myocytes from the patients with positive aFGF protein. In conclusion, the expression of FGF was significantly increased in myocytes obtained from the left ventricle of patients with cardiomyopathy. Acidic FGF may contribute to the hypertrophy of myocytes as the repair response to myocardial injury in patients with idiopathic cardiomyopathy. (Am Heart J 1997;134:779-86.)

Loss of MeV-energy protons to the first wall during H-minority second harmonic ion cyclotron range of frequency (ICRF) heating has been measured for the first time by neutron signals emitted by 11 B(p,n)C reaction in B 4 C coated divertor tiles and boronized tiles in the JT-60U tokamak. Since the reaction has a threshold energy of 3.0 MeV, the neutron signal indicates loss of fast protons whose energy is more than 3 MeV. Measurements of gamma-ray lines emitted from reaction between the fast protons and plasma impurities are also used for measurements of confined protons accelerated up to 5 MeV.

Antioxidants that act as free radical scavengers have the potential to inhibit lipid peroxidation. It has previously been proposed that a relationship exists between free radicals, lipid peroxidation and reperfusion-induced arrhythmias. We have therefore examined the ability of the lipid-soluble antioxidant, alpha-tocopherol, to decrease the incidence of reperfusion-induced arrhythmias. We have shown that the myocardial alpha-tocopherol content can be significantly increased from its control value of 65.3±5.6 nmoles/g wet wt of heart to 115.0±15.6 nmoles/g wet wt of heart (p<0.01) by chronic intraperitoneal pretreatment and that it can be decreased, to 21.1±3.7 nmoles/g wet wt of heart (p<0.01), by chronic dietary manipulation. Rat hearts isolated from either of these groups, or from placebo-treated control animals, were subjected to 5 or 10 min coronary artery occlusion and were subsequently reperfused; there were no significant differences between the incidence and duration of VF and VT or the incidence and number of VPBs in these three groups. The effect of alpha-tocopherol manipulation on metabolic and functional recovery of working hearts subjected to 20 min global ischemia was subsequently examined and no significant changes were observed. Cardiac output recovered to 82±4, 81±6 and 76±5% of its preischemic value in the control, enriched and depleted groups, respectively. In conclusion, myocardial alpha-tocopherol content appears to bear no relation to the severity of reperfusion-induced arrhythmias or to the resistance of the heart to ischemic injury.

By injection of high power lower hybrid (LH) waves of up to 6.0 MW into neutral beam heated (20 MW) plasmas in the medium electron density regime (e? 3.5 × 1019m-3) the plasma energy content is increased at the same incremental energy confinement time as it is increased with neutral beam heating alone. When LH heating is used in addition to thermal electron and ion heating, the beam ions are accelerated to energies considerably higher than the beam injection energy. In contrast to LH injection into ohmically heated plasmas in the same density regime, where substantial high energy electron production is observed, there are much less high energy electrons in the case of combined heating. The heating efficiency of LH waves during combined heating tends to decrease as the electron density is increased. Ray tracing analysis suggests that the accessibility condition prevents effective heating in a high density plasma. Calculation of wave damping, taking into account the beam component of the ion velocity distribution function, indicates that the waves are absorbed by beam ions before they are absorbed by electrons.

The active beam scattering method was applied to ion temperature measurements in JT-60 plasmas. The ion temperature found was in reasonable agreement with that obtained from Doppler broadening of the Ti XXI and Ti XXII resonance lines in the temperature range of 1.5 to 10 keV. With the help of the scattering system, the central ion temperature of JT-60 plasmas during 40 keV and 70-75 keV NBI heating was measured. Higher ion temperature was obtained during 70 to 75 keV than during 40 keV NBI heating. These data and a possible explanation are presented. A numerical simulation of this diagnostic indicates that the ion temperature as deduced from the diagnostic is almost equal to the bulk temperature when the ratio of high energy ion component to the total ion stored energy is less than 0.3.

Ion temperatures around 10 keV were obtained in JT-60 limiter plasmas by high power neutral beam heating (H0? H+), which is much higher than the maximum value of 6.6 keV obtained in JT-60 diverted plasmas. The experiment was performed in the parameter region of Ip= 1?2 MA, e(before heating) = (0.7?1.5)×1019m?3, e(end of heating) = (2.5?4.1)×1019m?3and = 19?21.8 MW. The Zeffvalues of the limiter plasmas were high (i.e. 4 to 7) compared with those of the diverted plasmas (i.e. 1 to 2). Transport analysis indicates that, since the deposition power to electrons, Pbe, increases with Zeff, high Zeffis effective in raising the electron temperature. Furthermore, it is shown that since the equipartition loss is reduced by both the increase in electron temperature and the decrease in the effective ion density, np+ nzZ2mp/mz, with increasing Zeff, high ion temperatures are obtained in limiter plasmas with high Zeff.

Collective Thomson scattering (CTS) diagnostic based on a pulsed CO2laser (wavelength 10.6 μm) has been developed to establish a diagnostic method of confined α-particles in burning plasmas. A high-repetition and high-energy transversely excited atmospheric (TEA) laser has been developed as a source of the CTS diagnostic. In order to obtain single-mode output, which is needed for CTS diagnostic, seed laser is injected into the cavity with unstable resonator. Pulse energy of 17 J with a repetition rate of 15 Hz has been achieved in a single-mode operation. This result gives a prospect for the CTS diagnostic on International Thermonuclear Experimental Reactor (ITER), which requires energy of 20 J with repetition rate of 40 Hz. Proof-of-principle test will be carried out in the JT-60U tokamak by using the newly developed laser. Preliminary consideration of the CTS diagnostic in the tandem mirror GAMMA 10 shows that axial profiles of ion temperature will be obtained using a circumferential collection mirror of scattered power.

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.