The extensive design effort for KSTAR has been focused on two major aspects of the KSTAR project mission - steady-state-operation capability and advanced tokamak physics. The steady state aspect of the mission is reflected in the choice of superconducting magnets, provision of actively cooled in-vessel components, and long pulse current drive and heating systems. The advanced tokamak aspect of the mission is incorporated in the design features associated with flexible plasma shaping, double null divertor and passive stabilizers, internal control coils and a comprehensive set of diagnostics. Substantial progress in engineering has been made on superconducting magnets, the vacuum vessel, plasma facing components and power supplies. The new KSTAR experimental facility with cryogenic system and deionized water cooling and main power systems has been designed, and the construction work is under way for completion in 2004.

Since the first H-mode discharges in 2010, the duration of the H-mode state has been extended and a significantly wider operational window of plasma parameters has been attained. Using a second neutral beam (NB) source and improved tuning of equilibrium configuration with real-time plasma control, a stored energy of W tot ∼ 450 kJ has been achieved with a corresponding energy confinement time of τ E ∼ 163 ms. Recent discharges, produced in the fall of 2012, have reached plasma β N up to 2.9 and surpassed the n = 1 ideal no-wall stability limit computed for H-mode pressure profiles, which is one of the key threshold parameters defining advanced tokamak operation. Typical H-mode discharges were operated with a plasma current of 600 kA at a toroidal magnetic field B T = 2 T. L-H transitions were obtained with 0.8-3.0 MW of NB injection power in both single-and double-null configurations, with H-mode durations up to ∼15 s at 600 kA of plasma current. The measured power threshold as a function of lineaveraged density showed a roll-over with a minimum value of ∼0.8 MW at ne ∼ 2×10 19 m −3 . Several edge-localized mode (ELM) control techniques during H-mode were examined with successful results including resonant magnetic perturbation, supersonic molecular beam injection (SMBI), vertical jogging and electron cyclotron current drive injection into the pedestal region. We observed various ELM responses, i.e. suppression or mitigation, depending on the relative phase of in-vessel control coil currents. In particular, with the 90 • phase of the n = 1 RMP as the most resonant configuration, a complete suppression of type-I ELMs was demonstrated. In addition, fast vertical jogging of the plasma column was also observed to be effective in ELM pace-making. SMBI-mitigated ELMs, a state of mitigated ELMs, were sustained for a few tens of ELM periods. A simple cellular automata ('sand-pile') model predicted that shallow deposition near the pedestal foot induced small-sized high-frequency ELMs, leading to the mitigation of large ELMs. In addition to the ELM control experiments, various physics topics were explored focusing on ITER-relevant physics issues such as the alteration of toroidal rotation caused by both electron cyclotron resonance heating (ECRH) and externally applied 3D fields, and the observed rotation drop by ECRH in NB-heated plasmas was investigated in terms of either a reversal of the turbulence-driven residual stress due to the transition of ion temperature gradient to trapped electron mode turbulence or neoclassical toroidal viscosity (NTV) torque by the internal kink mode. The suppression of runaway electrons using massive gas injection of deuterium showed that runaway electrons were avoided only below 3 T in KSTAR. Operation in 2013 is expected to routinely exceed the n = 1 ideal MHD no-wall stability boundary in the long-pulse H-mode ( 10 s) by applying real-time shaping control, enabling n = 1 resistive wall mode active control studies. In addition, intensive works for ELM mitigation, ELM dynamics, toroidal ro...

A new electron cyclotron emission (ECE) diagnostics system was installed for the Second Korea Superconducting Tokamak Advanced Research (KSTAR) campaign. The new ECE system consists of an ECE collecting optics system, an overmode circular corrugated waveguide system, and 48 channel heterodyne radiometer with the frequency range of 110-162 GHz. During the 2 T operation of the KSTAR tokamak, the electron temperatures as well as its radial profiles at the high field side were measured and sawtooth phenomena were also observed. We also discuss the effect of a window on in situ calibration.

Semiconducting SnO2 nanowires deposited with Pd and Sn nanoparticles on their surface are shown to be a highly sensitive hydrogen sensor with fast response time at room temperature. Compared with the SnO2 nanowire deposited with Pd or Sn nanoparticles alone, the Pd/Sn-deposited SnO2 nanowire exhibits a significant improvement in the sensitivity and reversibility of sensing hydrogen gas in the air at room temperature. Our investigation indicates that two factors are responsible for the synergistic effect of Pd/Sn codeposition on SnO2 nanowires. One is that in the presence of Pd the oxidation of Sn nanoparticles on the surface of the SnO2 nanowire is incomplete leading only to suboxides SnOx (1 ≤ x < 2), and the other is that the surface of the Pd/Sn-deposited SnO2 nanowire is almost perfectly hydrophobic.

In children, using the equiangular triangle to identify the sacral hiatus may be inappropriate because the actual triangle formed by the sacral hiatus and PSISs is not equiangular.