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The plasma response associated with the resonant magnetic perturbation (RMP) field was investigated using the small edge perturbations induced by a modulated supersonic molecular beam injection (SMBI) in KSTAR. The modulated SMBI provides a time-varying perturbation of the plasma density source in the region just inside the last closed flux surface and a modulated flow damping rate. Radial propagation of the toroidal rotation perturbation induced by SMBI from the q = 3 surface to the q = 2 surface was observed. Theoretical analysis using the general perturbed equilibrium code of the RMP intensity profiles of the RMP field is consistent with the phase profile of the toroidal rotation perturbation.

KSTAR has clarified a set of unresolved 3D physics issues utilizing the ITER-like in-vessel, three-row, resonant magnetic perturbation (RMP) configurations. Since RMP-driven, edge-localized-modes (ELMs)-crash control elevates the divertor heat flux peak through its impact on edge plasma parameters and transport, a series of intentionally misaligned RMP configurations (IMCs) have been explored to investigate the relationship between RMP ELM control and divertor heat fluxes, while searching for an ideal IMC that could be favorable in both aspects. First of all, the contrasting influence of kink vs anti-kink phasing on the ELM-crash suppression has been articulated, demonstrating the synergistic benefit of ‘kink’ phasing on ELM-crash-suppression. On the other hand, the three-row IMC in the anti-kink phasing becomes more insensitive to the ELM-crashes at the sub-marginal level of RMP, consistent with theory. Meanwhile, the divertor ‘wetted’ area of ELM-crash-suppression gets narrower than that of ELM-crash-mitigation, suggesting that ELM-crash-mitigation remains advantageous over ELM-crash-suppression in terms of time-averaged divertor thermal loading. In comparison, based on a set of two-row IMCs, no evidence of divertor heat flux broadening was found during ELM-crash-suppression, supporting a hypothesis that the dispersal of the divertor heat flux in three-row IMCs cannot be driven by helically structured two-row RMPs alone. Among ITER-like three-rows, lower two-row RMPs have been found to be much more effective in suppressing the ELM-crashes than upper two-row RMPs. Although it is quite preliminary, the up/down asymmetric dependence of RMP coupling may be generically attributed to lower-single-null plasmas. Such a holistic understanding of RMP-driven, ELM-crash-control in KSTAR is expected not only to elucidate various subtle points in the vicinity of ELM-crash-suppression, but also to clarify the relevant divertor thermal loading issues for ITER and beyond.

Mitigation of deleterious heat flux from edge-localized modes (ELMs) on fusion reactors is often attempted with 3D perturbations of the confining magnetic fields. However, the established technique of resonant magnetic perturbations (RMPs) also degrades plasma performance, complicating implementation on future fusion reactors. In this paper, we introduce an adaptive real-time control scheme on the KSTAR tokamak as a viable approach to achieve an ELM-free state and simultaneously recover high-confinement (β N ∼ 1.91, β p ∼ 1.53, and H 98 ∼ 0.9), demonstrating successful handling of a volatile complex system through adaptive measures. We show that, by exploiting a salient hysteresis process to adaptively minimize the RMP strength, stable ELM suppression can be achieved while actively encouraging confinement recovery. This is made possible by a self-organized transport response in the plasma edge which reinforces the confinement improvement through a widening of the ion temperature pedestal and promotes control stability, in contrast to the deteriorating effect on performance observed in standard RMP experiments. These results establish the real-time approach as an up-and-coming solution toward an optimized ELM-free state, which is an important step for the operation of ITER and reactor-grade tokamak plasmas.

KSTAR experiments have been conducted aiming at establishing a real-time control system that uses multiple actuators (NBI and ECH) to control the plasma profiles (Te and q profiles) and validating an applied physics-based plasma profile response model. Toward establishing the multiple plasma profile control system, the control experiment of the electron temperature profile has been performed in KSTAR as a first step. Although the plasma profile control system was in the commissioning phase, the electron temperature was feedback controlled successfully in real-time while the normalized radial profile of electron temperature remained nearly constant. In the circumstance, the implemented physics-based response model was successfully validated against control experiments with a step variation on the control target and an application of multiple actuators. The robustness of the controller is examined against an external disturbance in which a static version of the control matrix was used.

Results on the integration and the operation of the KSTAR plasma control system (PCS) upgrade are given. Real-time hardware, new realtime-capable operating system, and a brand-new data acquisition are assembled in order to extend the performance and compatibility with modern computer systems. The first full commissioning and eventual routine use performed in 2016 so that the system can now acquire more than 400 channels for more than 100 seconds of data with 5 kHz sampling. The performance test results are summarized, featuring In/Out streaming echo tests and the synchronization verifications. Examples of general performance improvements are demonstrated, and additional features added to the software are also described.

Disruption avoidance is one of the most critical issues in KSTAR due to its high current, temperature and long operation characteristics of the superconducting tokamak. To minimize possible damages to the machine, we imposed a real time handling algorithm of off-normal events, named “forced landing” to ramp down the plasma with well-controlled plasma current and position. Two different plasma control schemes are implemented for different purposes and situations. Both schemes have been successfully demonstrated with careful classifications of actions on the machine in real experiments and they show routine performance with effective reduction of impacts on the machine. Such “machine-protection” schemes enable more aggressive operations such as mega-ampere or high beta experiment, resulting in an expansion of the KSTAR operation regime due to reduced less concerns regarding mechanical safety issues.

We explore the inboard-limited internal transport barrier (ITB) as an alternative advanced operation scenario for KSTAR. This paper presents in detail the progress of the ITB experiment at KSTAR. In an earlier study, the ITB formed in both ion and electron thermal channels, and an early neutral-beam injection (NBI) power of over 4 to 5 MW under a limited L-mode was crucial to ITB access. In the present study, we access the ITB experimentally with about 3 MW of NBI power by using the upper single null (USN), which is an unfavorable H-mode condition with a higher L–H power threshold. Finding an ITB access condition with a lower heating power should allow for a more efficient control of the heat flux and for maintaining stable plasma performance. The key control parameters of the experiment are the vertical position and the location of outboard striking point of the plasma. The shape-control attempts to divert the plasma to a vertically shifted USN with a marginal touch of the inboard limiter so that the plasma can remain in the L-mode at the boundary, while the striking-point control maintains the ITB performance for a longer period of time.

The plasma control system (PCS) has been one of essential systems in annual KSTAR plasma campaigns: starting from a single-process version in 2008, extensive upgrades are done through the previous 7 years in order to achieve major goals of KSTAR performance enhancement. Major implementations are explained in this paper. In consequences of successive upgrades, the present KSTAR PCS is able to achieve ∼48 s of 500 kA plasma pulses with full real-time shaping controls and real-time NB power controls. It has become a huge system capable of dealing with 8 separate categories of algorithms, 26 actuators directly controllable during the shot, and real-time data communication units consisting of +180 analog channels and +600 digital input/outputs through the reflective memory (RFM) network. The next upgrade of the KSTAR PCS is planned in 2015 before the campaign. An overview of the upgrade layout will be given for this paper. The real-time system box is planned to use the CERN MRG-Realtime OS, an ITER-compatible standard operating system. New hardware is developed for faster real-time streaming system for future installations of actuators/diagnostics.

We study a Reaction-Diffusion model describing the nonlinear oscillations of a transport barrier in a finite shear-layer (width dE ≪ a), where a is the plasma minor radius, based on a 1D reduced model derived to explain nonlinear barrier oscillations in 3D turbulence simulations [P. Beyer, S. Benkadda, G. Fuhr-Chaudier et al., Phys. Rev. Lett. 94, 105001 (2005)]. We show that this single nonlinear equation encompasses most of the physics of these barrier relaxations. The nonlinear oscillations have common characteristics with type-III edge localized modes (ELMs), such as a repetition frequency which decreases with increasing power. In addition to the flow shear, the shear-layer width is also shown to control the nature of the oscillations. (© 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)

The age of the human footprints found on the bedding plane of a reworked volcaniclastic deposit on Jeju Island, Korea, has been a subject of controversies in Korea for more than a decade. Two researchers that discovered the footprints and their colleagues have argued that the footprints belong to Paleolithic ‘hominids’ that lived in the Late Pleistocene (c. 19,000–25,000 cal yrs BP). They made their argument on the basis of the pre-Holocene radiocarbon ages of humic and humin organic matter in bulk sediment, but have ignored Holocene radiocarbon ages of mollusk shells and other age data from the volcaniclastic deposit and adjacent geologic units. They also refused to correlate the deposit with any well-defined and well-dated stratigraphic units in the study area but correlated it with an imaginary stratigraphic unit which they named “unnamed strata”. This study discusses the problems of their work published in a series of papers in the last decade by reviewing the stratigraphy and age of the geologic units in southwestern Jeju Island and presenting new sedimentologic and stratigraphic observations and new radiocarbon dating of mollusk shells. This study shows that the “unnamed strata” is the basal part of the Songaksan Tuff, which is the rimbeds of a coastal tuff ring that erupted c. 3700 yrs BP, and that the strata at the footprints site comprise the distal Songaksan Tuff at the base and a reworked volcaniclastic deposit (the Hamori Formation) above it. The human footprints, which are found in the topmost part of the Hamori Formation, should therefore postdate the eruption of the Songaksan volcano and belong to late Neolithic ‘humans’ who lived in the mid- to late Holocene.

The tearing mode (TM) plasma instability was observed in low confinement (L-mode) plasmas when non-axisymmetric magnetic perturbation (MP) was applied using external coils during 2011 campaign of KSTAR. Based on the collected information of the magnetic island location in a plasma, a discharge was designed for suppression of a (2,1) TM mode by adjusting electron cyclotron (EC) launcher angles to the estimated island position. Here, the (m,n) notation describes the poloidal mode number and the toroidal mode number of the TM, respectively. The discharge is analysed with experimental observations and numerical simulations. Mirnov coil (MC) arrays and electron cyclotron emission (ECE) are used for analysis of the island width and the location as well as the mode number. The EC deposition and its alignment with the island are estimated by X-ray imaging crystal spectroscopy (XICS) and ECE measurements. An integrated numerical system is employed for modelling of this discharge to analyse a temporal evolution of the mode activity by integrating plasma equilibrium, transport, heating and current drive, and the magnetic island evolution, in a self-consistent way. The effect of EC current drive is discussed by comparing with another TM discharge but without ECCD. Some possibilities for classifying this mode to neoclassical tearing mode (NTM) and stabilisation effect of ECCD are suggested based on the experimental observation and the simulation results.

Superconducting tokamaks like KSTAR, EAST and ITER need elaborate magnetic controls mainly due to either the demanding experiment schedule or tighter hardware limitations caused by the superconducting coils. In order to reduce the operation runtime requirements, two types of plasma simulators for the KSTAR plasma control system (PCS) have been developed for improving axisymmetric magnetic controls. The first one is an open-loop type, which can reproduce the control done in an old shot by loading the corresponding diagnostics data and PCS setup. The other one, a closed-loop simulator based on a linear nonrigid plasma model, is designed to simulate dynamic responses of the plasma equilibrium and plasma current (Ip) due to changes of the axisymmetric poloidal field (PF) coil currents, poloidal beta, and internal inductance. The closed-loop simulator is the one that actually can test and enable alteration of the feedback control setup for the next shot. The simulators have been used routinely in 2012 plasma campaign, and the experimental performances of the axisymmetric shape control algorithm are enhanced. Quality of the real-time EFIT has been enhanced by utilizations of the open-loop type. Using the closed-loop type, the decoupling scheme of the plasma current control and axisymmetric shape controls are verified through both the simulations and experiments. By combining with the relay feedback tuning algorithm, the improved controls helped to maintain the shape suitable for longer H-mode (10–16 s) with the number of required commissioning shots largely reduced.

Electrical probe measurements are carried out at the scrape-off-layer (SOL) and divertor regions in order to investigate the characteristics of edge plasmas during H-mode discharges in the Korea Superconducting Tokamak Advanced Research (KSTAR) device. Radial profiles of plasma parameters such as electron temperature Te, plasma density ne, and parallel flow velocity v‖ are measured by using a fast reciprocating Langmuir probe assembly (FRLPA) at the SOL region. From the FRLPA measurements, it is found that the decay length of temperature λTe and that of density λne are 2 ∼ 4 cm and 1 ∼ 3 cm, respectively. The magnitude of v‖ near the last closed flux surface (LCFS) is 4 ∼ 15 km/s. The radial flux due to edge turbulence at the SOL region is investigated by using spectra analysis on electrostatic fluctuation levels such as ion saturation current Ĩis and floating potential $ \tilde{\rm V}_f$ obtained from the FRLPA measurement. The value of the flux is estimated as ∼ 1020 particle m−2 s −1 near the LCFS. The poloidal distribution of the ion saturation current density jis is measured by fixed edge Langmuir probe array (ELPA) at the divertor region, and it is found that the positions of strike points from the ELPA measurement agree well with those reconstructed from the EFIT result using magnetic diagnostic data. From the spectrum analysis on the ELPA measurements at the divertor region during edge localized modes (ELMs) control in the H-mode discharges, it is observed that the magnitude of $ \tilde{\rm j}_{is}$(ω) near strike point decreases when the ELMs are suppressed or mitigated (© 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)

The neutral beam injection (NBI) system was designed to provide plasma heating and current drive for high performance and long pulse operation of the Korean Superconducting Tokamak Advanced Research (KSTAR) device using two co-current beam injection systems. Each neutral beam injection system was designed to inject three beams using three ion sources and each ion source has been designed to deliver more than 2.0 MW of deuterium neutral beam power for the 100-keV beam energy. Consequently, the final goal of the KSTAR NBI system aims to inject more than 12 MW of deuterium beam power with the two NBI for the long pulse operation of the KSTAR. As an initial step toward the long pulse (∼300 s) KSTAR NBI system development, the first neutral beam injection system equipped with one ion source was constructed for the KSTAR 2010 campaign and successfully commissioned. During the KSTAR 2010 campaign, a MW-deuterium neutral beam was successfully injected to the KSTAR plasma with maximum beam energy of 90 keV and the L-H transition was observed with neutral beam heating. In recent 2011 campaign, the beam power of 1.5 MW is injected with the beam energy of 95 keV. With the beam injection, the ion and electron temperatures increased significantly, and increase of the toroidal rotation speed of the plasma was observed as well. This paper describes the design, construction, commissioning results of the first NBI system leading the successful heating experiments carried in the KSTAR 2010 and 2011 campaign and the trial of 300-s long pulse beam extraction.

The in-vessel control coil (IVCC) system, which has been designed for dedication of various active feedback plasma control functions, successfully fabricated and installed in the vacuum vessel of the Korea Superconducting Tokamak Advanced Research (KSTAR). The IVCC system consists of sixteen segmented coils that were independently fabricated outside the vacuum vessel and installed without any inside welding or brazing joints. The segmented coil system has several advantages such as eliminating possibility of cooling water leakage at the welded or brazed joints, simplification in fabrication and installation, and easy repair and maintenance of the coil system. Each segment contains eight oxygen-free high conductive coppers, which are grouped to four pairs, called as sections. Consequently, a segmented coil forms four sections for position control, field error correction (FEC), and resistive wall mode (RWM) control in accordance with electrical connection outside the cryostat. The eight conductors (or four sections) with internal coolant holes were enclosed in a rectangular welded jacket made of stainless steel 316LN and electrically insulated from the conductors by epoxy/glass composite layers. This coil system was commissioned up to 5 kA (30 kA-turns) for 5 s to achieve tentative use for the fast vertical plasma position control in the 2010 campaign of the KSTAR. This paper describes the several remarkable results in the fabrication and installation of the IVCC as well as commissioning results.

Ilchulbong (Sunrise Peak) tuff cone is a United Nations Educational, Scientific, and Cultural Organization (UNESCO) World Heritage site that owes its scientific importance to the outstanding coastal exposures that surround it. It is a type locality for the sedimentary evidence of pyroclastic transport and depositional processes that occur during phreatomagmatic basaltic eruptions. Its classically shaped cone morphology was long considered to result from a single short-lived eruption. Reanalysis of the sedimentary sequence has now revealed two subtle paraconformities in the deposits, indicating that the eruption occurred in three separate phases. The break between phases I to II was "long," i.e., days to weeks, during which erosion and compaction of the lower cone occurred, leading to a volcanowide discontinuity surface and reworked deposits in the lower flanks. Possibly following cooling and solidification of the initial shallow conduit system, the phase II eruption resumed from a new vent location ∼600 m away, before being terminated by a very brief interval and final eruption of phase III from the same general site. The second pause led to a more subtle discontinuity, marked by differences in deposit character above and below it, and it was associated with a period of seismicity-induced slumping and slipping of deposits. Detailed geochemical study of the juvenile clasts through the sequence reveals that three separate alkali basaltic magma pulses were erupted, corresponding directly to the three eruption phases. Magmas 1 and 3 may be genetically related, with the former showing evidence for longer periods of shallow-level fractionation, whereas magma 2 originated from a slightly different mantle domain, although at a similar depth. These results demonstrate that breaks in monogenetic eruption sequences may represent deep magma system processes, and they raise fundamental questions concerning the mechanisms of triggering and eruption of multiple magma pulses in small-volume basaltic volcanoes. This study shows the importance of recognizing sedimentary evidence of time breaks in such eruption sequences as potential indications of shifts in eruption chemistry and vent location. These have important implications for the controls of vent migration at other monogenetic volcanoes and for hazard planning during future similar eruptions.

The Cretaceous Kusandong Tuff, Korea, is a thin (1–5 m thick) but laterally extensive (~ 200 km) silicic ignimbrite emplaced in a fluviolacustrine basin adjacent to a continental volcanic arc. The tuff has been used as an excellent key bed because of its great lateral continuity and unique lithology, characterized by the virtual absence of juvenile clasts and an abundance of quartz and feldspar crystals (up to 55–73 vol.%). The tuff is mostly massive and ungraded and locally shows crude internal layering, basal inverse grading and near-top normal grading of crystals, either erosional or non-erosional lower surfaces, and flat-lying to imbricated grain fabrics. Fragile intraformational clasts of mudstone and tuff are also included. These features provide only ambiguous information on the properties of the responsible pyroclastic density currents: i.e. whether they were dense and laminar or dilute and turbulent. The overall lateral continuity and sheet-like geometry of the tuff suggests, however, that the transport system of the currents was highly expanded, dilute, and turbulent. A plug-flow or slab-flow model cannot explain the origin of crude internal layering, imbricated grain fabrics, and the high crystal content, which is most likely the result of vigorous sorting processes within a dilute and turbulent current. Features indicative of deposition from a dense and laminar transporting medium are locally present, suggesting that a dense and laminar depositional system could develop locally at the base of the dilute and turbulent transport system. The virtual absence of juvenile clasts in the tuff is interpreted to be due to rapid ascent, sudden decompression, and full fragmentation of silicic magma into fine glass shards and crystals. Scarcity of basement-derived accidental components together with the absence of pumiceous fallout deposits beneath the tuff is interpreted to be due to shallow-level fragmentation of magma followed by immediate generation of pyroclastic density currents from shallow-level blasts at the onset of eruption. The eruption occurred through multiple vent sites in a short period of time, producing a seemingly single but actually composite ignimbrite unit. Such an eruption was probably possible because of a regional tectonic event within the basin or in its vicinity. It is proposed that a composite ignimbrite with the characteristics of the Kusandong Tuff can be an exemplary product of syntectonic volcanism that can provide an insight into the interpretation of structural and stratigraphic evolution of a sedimentary basin.

Two phases of a DIII-D discharge with and without magnetohydrodynamics (MHD) activity are analysed using ONETWO code. The toroidal momentum flux is extracted from experimental data and compared with the predictions by neoclassical theory, Gyro?Landau fluid transport model (GLF23) and Multi-Mode model (MMM95). It is found that without MHD activities GLF23 and MMM95 provide a reasonable description while with MHD activity no model alone can fully describe the experimental momentum flux. For the phase with MHD activity a simple model of resonant magnetic drag is tested and it cannot fully explain the plasma slowing down observed in experiment.

A free-boundary Tokamak Equilibrium Solver (TES), developed for advanced study of tokamak equilibra, is described with two distinctive features. One is a generalized method to resolve the intrinsic axisymmetric instability, which is encountered after all in equilibrium calculation with a free-boundary condition. The other is an extension to deal with a new divertor geometry such as snowflake or X divertors. For validations, the uniqueness of a solution is confirmed by the independence on variations of computational domain, the mathematical correctness and accuracy of equilibrium profiles are checked by a direct comparison with an analytic equilibrium known as a generalized Solovev equilibrium, and the governing force balance relation is tested by examining the intrinsic axisymmetric instabilities. As a valuable application, a snowflake equilibrium that requires a second order zero of the poloidal magnetic field is discussed in the circumstance of KSTAR coil system., 20 pages, 6 figures

Thrombocytopenia (platelet60,000/mm(3)) and uncontrolled massive ascites (ascitic fluid1000 mL/d over 10 days) after liver transplantation (OLT), although uncommon, usually represent serious complications. Splenectomy is a useful treatment despite its many side effects. Recently, partial splenic artery embolization (PSAE) is considered to be a nonsurgical, less invasive treatment. In this study, we retrospectively reviewed the results of PSAE after OLT. Between October 2008 and February 2010, 11 patients underwent PSAE after OLT due to thrombocytopenia (n = 6) or refractory ascites (RA; n = 5). Six patients (54.5%) were males and 3 (27.3%) were children. The primary liver disease was virus-related liver cirrhosis (n = 6), biliary atresia (n = 3), fulminant hepatitis (n = 1), or alcoholic liver cirrhosis (n = 1). Seven grafts were from living and four from deceased donors. The major axial size of spleen was 12.1 to 23.4 cm and its average embolized volume, 76.4% (range = 70%-80%). As the result, the platelet count significantly increased after PSAE in all patients maintaining values greater than 100,000/mm(3) in four thrombocytopenic patients (66.7%). Cases of RA showed marked decreases after PSAE (100%). The follow-up was 6 to 28 months. After PSAE, patients experienced abdominal pain (n = 9, 81.8%), fever (n = 2, 18.2%), and abdominal distension (n = 2, 18.2%). However, there was no serious complication after PSAE such as splenic abscess, rupture, pancreatic infarction, sepsis, or death. In conclusion, PSAE was effective and safe and can be the choice for thrombocytopenia or RA related to hypersplenism after OLT.

In- and outboard Plasma Facing Components (PFCs) of KSTAR (Korea Superconducting Tokamak Advanced Reasearch) have been fully installed in 2010 for D shaped diverted plasmas. Before the start of plasma operation, the PFCs were baked up to 200 °C by hot nitrogen gas circulation system to remove impurities including water. The surface temperature of the PFC tiles was monitored by 200 thermo-couple sensors during the plasma operation (plasma shot or Glow Discharge Cleaning(GDC)), and the temporal and spatial (poloidal) temperature profiles are obtained. Depending on the heat flux on each tile, the surface temperature shows time-dependency. After 1-hour morning He GDC, the temperature of the PFCs at inboard side has reached at 40 °C. After an H-mode shot, the temperature of divertor tiles around the striking points was substantially increased. The time-averaged total heat flux after an specific H-mode in 2010 was estimated to be approximately 10kW/m2.

The Korean Superconducting Tokamak Advanced Research (KSTAR) device is aimed at advanced tokamak (AT) research. Three years have passed since it achieved its first plasma in 2008. Because it is a superconducting machine and is pursuing AT research, it has unique features in terms of the machine engineering and operation. The toroidal field (TF) magnet coils are made of Nb 3 Sn, which provide high toroidal fields up to 3.5 T, and have been fully tested. The poloidal field (PF) magnet coils, consisting of both Nb3Sn and NbTi, which have a maximum current of 25 kA in their design, were tested up to 15 kA. A thermal hydraulic analysis is being conducted for PF magnet coil operation. All plasma facing components (PFCs) are equipped with water cooled graphite tiles and have the capability of being baked up to 350 °C. A startup scenario, which considered both the effect of the ferromagnetic material in the cable in conduit conductor (CICC) jacket in the magnet coils as well as a non-ferromagnetic up-down asymmetry in the cryostat structure, was developed and demonstrated its effectiveness by the last two year's reliable operations. Passive stabilizers and In-Vessel Control Coils (IVCC) are key components to realize AT Operation in KSTAR. The segmented IVCC coils were connected to form circular coils for internal vertical control in 2010 and diverted plasmas with high elongation (κ∼1.8, δ>0.6) were achieved. A neutral beam injection (NBI) system was developed aiming at 2 MW, 300 s per ion source which meets the long-pulse requirement of KSTAR. An NBI ion source with a power of 1.7 MW at 100 kV has been commissioned. Finally, ELMy H-modes were successfully produced with 1.3 MW NBI power at a plasma current of 0.6 MA in the 2010 campaign. The first H-mode discharge (#4200) in KSTAR was achieved one year earlier than officially planned and it was done at B T =2.0 T with Ip=0.6 MA in a well-balanced double null configuration after boronization on the PFC. Successful operations in the early days of KSTAR including H-mode experiments revealed the capability of advanced and steady-state operation which is essential for the International Thermonuclear Experimental Reactor (ITER) and future fusion reactors

The development of the plasma shape control system of the Korea Superconducting Tokamak and Advanced Research (KSTAR) continues from the first utilization for plasma current/ major radii to the full-scale utilizations of the poloidal superconducting magnets and the in-vessel stabilization coils for the highly elongated (κ ∼ 2.0) plasmas planned in 2009/2010. In this paper the shape control of KSTAR is analyzed as a complete integrated form, including the operation design and experiences. In the first plasma campaign held in 2008, the plasma shape control system has been prepared as part of the pulse operation controls for the first daily operation. A time-synchronized shot sequence supervisions and actuator integrations has been done by the full-digital centralization scheme via the EPICS communicating layers and the dedicated fast communication layers. In the end a reliable real-time plasma feedback system have been accomplished for making/sustaining plasma current and major radius. The status of the shape control upgrade proposed for upcoming years is shown as well as the actuator control developments and the newly-introduced in-vessel vertical stabilization control scheme.

Botulinum toxin type A (BTX-A) injection into the masseter muscles is used to treat masseteric hypertrophy. No serious side effects of BTX-A have been reported, but patients sometimes complain of xerostomia. The aim of this study was to evaluate the effect of injecting BTX-A into the masseter for the treatment of masseteric hypertrophy on the flow of saliva from the parotid gland. 34 volunteers enrolled in this study. A total of 25 units of BTX-A was injected into each side bilaterally at two points at the center of the lower third of the masseter muscle. Saliva was collected from the parotid gland over a period of 10 min to determine the flow rate for 18 weeks after injection. The flow rate was calculated by dividing the amount in milliliters by the collection time in minutes. There were no significant changes in the stimulated parotid saliva flow at 4, 8, 12 or 18 weeks compared with the baseline. Within this limited study, it can be concluded that BTX-A injection into the masseter does not cause any significant decrease in the production of saliva from the parotid gland.

By using gain nonlinearity characteristics of a semiconductor optical amplifier, an all-optical NAND gate at 10 Gbit/s is demonstrated. The all-optical NAND gate operates in single mechanism, which is cross-gain modulation. In the NAND gate (AB+Ā), Boolean AB is obtained by using signal A as a probe beam and signal B as a pump beam in SOA-1. Also, Boolean Ā is obtained by using the clock signal as a probe beam and signal A as a pump beam in SOA-2. By adding the two outputs from SOA-1 and SOA-2, Boolean Ā+AB (logic NAND) can be acquired. The extinction ratio is about 6.1 dB.