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Definitions of angle radius and coordinates axis are presented to propose a new transient stability method that is simple and reliable for transient stability assessment. The concept of angle radius is further developed to introduce the novel concept of projection energy function (PEF), which in turn allow to the assessment of critical clearing time and generation limit of system in a new way. The advantage of the new method is that no concept of advanced generator group is required in the assessment contingency stability index. Case studies on the ten-generator New England test power system are reported to verify the validity of the PEF method.

The National Spherical Torus Experiment (NSTX) at Princeton University, Princeton, NJ, is designed to assess the potential of the low-aspect-ratio spherical torus concept for magnetic plasma confinement. The plasma has been heated by up to 7 MW of neutral beam injection (NBI) at an injection energy of 100 keV and up to 6 MW of high harmonic fast wave (HHFW) at 30 MHz. NSTX has achieved /spl beta//sub T/ of 32%. A variety of MHD phenomena have been observed to limit /spl beta/. NSTX has now begun addressing /spl tau//sub E/ scaling, /spl beta/ limits, and current drive issues. During the NBI heating experiments, a broad T/sub i/ profile with T/sub i/ up to 2 keV, T/sub i/>T/sub e/ and a large toroidal rotation were observed. Transport analysis suggests that the impurity ions have diffusivities approaching neoclassical. For L-Mode plasmas, /spl tau//sub E/ is up to two times the ITER97L L-Mode scaling and exceeds the ITER98pby2 H-Mode scaling in some cases. Transitions to H-Mode have been observed which result in an approximate doubling of /spl tau//sub E/ after the transition in some conditions. During HHFW heating, T/sub e/>T/sub i/ and T/sub e/ up to 3.5 keV were observed. Current drive has been studied using both coaxial helicity injection with up to 390 kA of toroidal current and HHFW. HHFW has produced H-modes with significant bootstrap current fraction at low I/sub p/, high q, and high /spl beta//sub p/.

Double angle connections, which are welded to the beam web and bolted to the column flange, are studied to establish the effect of bolt gage distance and angle thickness. An analysis is performed to establish the moment–rotation relationship for the double angle connections and the stress distribution of each specimen is observed. They are subjected to shear loads and the elastic–perfectly plastic constitutive law is assumed. The software package ABAQUS is used to analyze the nonlinear behavior of a double angle connection. To verify the finite element model analysis, experimental tests with the same geometric and material conditions as the analysis are also conducted.

The Korea Superconducting Tokamak Advanced Research (KSTAR) project is the major effort of the national fusion programme of the Republic of Korea. Its aim is to develop a steady state capable advanced superconducting tokamak to establish a scientific and technological basis for an attractive fusion reactor. The major parameters of the tokamak are: major radius 1.8 m, minor radius 0.5 m, toroidal field 3.5 T and plasma current 2 MA, with a strongly shaped plasma cross-section and double null divertor. The initial pulse length provided by the poloidal magnet system is 20 s, but the pulse length can be increased to 300 s through non-inductive current drive. The plasma heating and current drive system consists of neutral beams, ion cyclotron waves, lower hybrid waves and electron cyclotron waves for flexible profile control in advanced tokamak operating modes. A comprehensive set of diagnostics is planned for plasma control, performance evaluation and physics understanding. The project has completed its conceptual design and moved to the engineering design and construction phase. The target date for the first plasma is 2002.

Based on the recently developed heating theory (see Yoon et al., Phys. Rev. E, vol.55, no.6, p.7536-48 (1997)), a theoretical formula of E- and H-discharge transition power in a transformer-coupled plasma (TCP) discharge has been developed. The present result agrees well with an experimental observation for argon discharge.

Summary form only given. Experiments are underway to demonstrate an amplified radiation power of 200 kW operating at 28 GHz. A long pulse operation of up to 500 msec is required for plasma heating experiments of Hanbit. A five-cavity interaction circuit is designed by the use of small signal and large signal non-linear simulation codes. Simulations predict a saturated gain of 54 dB and an electronic efficiency of 35%. An input drive cavity designed by the use of HFSS consists of a WR-28 waveguide, a TE311 single-ridged coaxial cavity, and a circular TE011 central cavity. In this high gain amplifier, an input power of less than 1 W is enough to saturate the amplifier, which is the power level available from a high power solid state power amplifier. Three penultimate cavities are loaded by lossy ceramic rings. A water cooled beam collector is designed to spread the beam over a wide surface by carefully tapering an external magnetic field. An input window which is a typical pillbox configuration is designed. Simulations predicts a bandwidth of more than 7% with a center frequency of 28 GHz at -20 dB return loss. An half wavelength thick BeO window is designed for extracting the amplified radiation power of 200 kW with a pulse length of 500 msec. Thermal analyses on ceramic loaded cavities, RF vacuum windows, beam collector performed by ANSYS are currently underway to design the tube to be operated at a duty of 50%. Cold tests of the interaction circuits are presented.

The KSTAR (Korea Superconducting Tokamak Advanced Research) project is the major effort of the Korean National Fusion Program to design, construct, and operate a steady-state-capable superconducting tokamak. The project is led by Korea Basic Science Institute and shared by national laboratories, universities, and industry along with international collaboration. It is in the conceptual design phase and aims for the first plasma by mid 2002. The key design features of KSTAR are: major radius 1.8 m, minor radius 0.5 m, toroidal field 3.5 T, plasma current 2 MA, and flexible plasma shaping (elongation 2.0; triangularity 0.8; double-null poloidal divertor). Both the toroidal and the poloidal field magnets are superconducting coils. The device is configured to be initially capable of 20 s pulse operation and then to be upgraded for operation up to 300 s with non-inductive current drive. The auxiliary heating and current drive system consists of neutral beam, ICRF, lower hybrid, and ECRF. Deuterium operation is planned with a full radiation shielding.