Comparing pedestal structure in JET-ILW H-mode plasmas with a model for stiff ETG turbulent heat transport.

A predictive model for the electron temperature profile of the H-mode pedestal is described, and its results are compared with the pedestal structure of JET-ILW plasmas. The model is based on a scaling for the gyro-Bohm normalized, turbulent electron heat flux [Formula: see text] resulting from electron temperature gradient (ETG) turbulence, derived from results of nonlinear gyrokinetic (GK) calculations for the steep gradient region. By using the local temperature gradient scale length [Formula: see text] in the normalization, the dependence of [Formula: see text] on the normalized gradients [Formula: see text] and [Formula: see text] can be represented by a unified scaling with the parameter [Formula: see text], to which the linear stability of ETG turbulence is sensitive when the density gradient is sufficiently steep. For a prescribed density profile, the value of [Formula: see text] determined from this scaling, required to maintain a constant electron heat flux [Formula: see text] across the pedestal, is used to calculate the temperature profile. Reasonable agreement with measurements is found for different cases, the model providing an explanation of the relative widths and shifts of the [Formula: see text] and [Formula: see text] profiles, as well as highlighting the importance of the separatrix boundary conditions. Other cases showing disagreement indicate conditions where other branches of turbulence might dominate. This article is part of a discussion meeting issue 'H-mode transition and pedestal studies in fusion plasmas'.

Nonlinear Kinetic Ion Response to Small Scale Magnetic Islands in Tokamak Plasmas: Neoclassical Tearing Mode Threshold Physics.

A new drift-kinetic theory of the ion response to magnetic islands in tokamak plasmas is presented. Small islands are considered, with widths w much smaller than the plasma radius r, but comparable to the trapped ion orbit width ρ_{bi}. An expansion in w/r reduces the system dimensions from five down to four. In the absence of an electrostatic potential, the ions follow stream lines that map out a drift-island structure that is identical to the magnetic island, but shifted by an amount ∼ few ρ_{bi}. The ion distribution function is flattened across these drift islands, not the magnetic island. For small islands, w∼ρ_{bi}, the shifted drift islands result in a pressure gradient being maintained across the magnetic island, explaining previous simulation results [E. Poli et al., Phys. Rev. Lett. 88, 075001 (2002)PRLTAO0031-900710.1103/PhysRevLett.88.075001]. To maintain quasineutrality an electrostatic potential forms, which then supports a pressure gradient in the electrons also. This influence on the electron physics is shown to stabilize small magnetic islands of width a few ion banana widths, providing a new threshold mechanism for neoclassical tearing modes-a key result for the performance of future tokamaks, including ITER.

Resilience of quasi-isodynamic stellarators against trapped-particle instabilities.

It is shown that in perfectly quasi-isodynamic stellarators, trapped particles with a bounce frequency much higher than the frequency of the instability are stabilizing in the electrostatic and collisionless limit. The collisionless trapped-particle instability is therefore stable as well as the ordinary electron-density-gradient-driven trapped-electron mode. This result follows from the energy balance of electrostatic instabilities and is thus independent of all other details of the magnetic geometry.

Jóge Kankei: a key concept for an understanding of Japanese-American achievement.

Jóge Kankei, or an emphasis on superior-inferior relationships, refers to the pervasive concern with ranking in Japanese society. This concept is associated with achievement motivation in that it is related to socialization practices that create in the individual a heightened sensitivity to the opinions of significant others. In this paper, the pervasive concern with ranking and the sensitivity to the opinions of others is first used as a conceptual tool to explain the alleged paradoxical behavior of the Japanese at various times in their history, and is then used as the basis of a study aimed at understanding the rapid acculturation of the Japanese Americans. The study is based upon interviews with 234 Issei (first generation, born in Japan), 241 Nisei (second generation, born of Issei parents), and 372 Sansei (third generation, born of Nisei parents). Additionally, these three groups were administered several tests and questionnaires designed to measure acculturation and the retention of Japanese values.

The social and psychological reality of European witchcraft beliefs.

In recent years there have been a number of books and articles on witchcraft in general and European witchcraft in particular. The majority of these works contain the implicit or explicit assumption that witchcraft was a cruel, irrational delusion that resulted in the deaths of perhaps hundreds of thousands or innocent victims (Anderson, 1970). While I do not for a moment dispute the horrible cruelties and hideous tortures inflicted on many of the accused, I do feel that it is essential to point out that in terms of the culture and belief structure of Late Medieval and Post Reformation Europe, not only was a belief in witchcraft not irrational and a delusion, but also it did in fact make good sense.

Value changes in third generation Japanese Americans.

To compare the acculturation of third generation Japanese Americans with a contemporary Caucasian college student population 275 Japanese Americans (106 males, 169 females), and 346 Caucasian American college students (136 males, 210 females), were given the Edwards Personal Preference Schedule, which describes personality in terms of 15 needs. The results indicated that while acculturation has taken place among the Japanese Americans, when their scores are compared with a contemporary Caucasian college sample, the Japanese Americans still express a significantly higher need for order, succorance, and abasement, and a significantly lower need for change and heterosexuality.

Stability of internal transport barriers to ideal MHD ballooning modes.

Internal transport barriers (ITB) in tokamaks can form near a minimum in the q profile, q(min), where magnetic shear is weak. We have analyzed their stability to short wavelength (n>>1, where n is the toroidal mode number) ideal MHD ballooning modes, by considering the s-alpha model equilibrium. We show that the ballooning transformation fails in regions of low shear but that one can then adopt a complementary approach based on the recurrence relation describing the toroidal coupling of radially localized modes on adjacent rational surfaces. Inclusion of the stabilizing effects of favorable average curvature or finite-n using this technique leads to stable high-pressure ITB configurations. The theory also shows the advantages of operating with low-order rational values of q(min).

Finite Larmor-radius theory of magnetic island evolution.

Gyrokinetic theory is used to investigate the effect of the polarization drift on magnetic island evolution. Three regimes are found. For island phase velocities between the ion- and electric-drift velocities, the polarization current is shown to be stabilizing. For phase velocities between the electric- and electron-drift velocities, the island emits drift waves. This results in a radiative drag force. For all other phase velocities the polarization current is destabilizing, in agreement with the fluid limit.

Bone-lead analysis: development of analytical methodology for milligram samples.

A graphite platform-in-furnace atomic absorption spectrometric (GFAAS) method for determining micrograms/g levels of Pb in 10-20 mg cortical and trabecular primate bone samples is described. The GFAAS method is based on an ambient temperature nitric acid digestion of the sample, matrix modification with palladium nitrate, stabilized temperature platform furnace atomization, and a systematic evaluation of the temperature program of the atomizer. The method of standard additions is mandatory. The detection limit (3 standard deviations of the blank) is 0.19 micrograms Pb/g dry weight for a 10-mg sample taken up in a 1-mL volume. Data are presented on the degree of accuracy and precision. The accuracy of the proposed GFAAS method has been assessed using the IAEA bone reference material, H-5, and by comparing the values obtained in a bone sample with an isotope dilution mass spectrometric (IDMS) procedure. The GFAAS method can be applied to the determination of Pb in 10-20 mg bone samples and for concentrations which are > or = 10 x detection limit. The method is simple, fast, and contamination-free since the entire operation from weighing to GFAAS measurement is carried out in the same centrifuge tube. The method has been applied to the determination of total-Pb in some adult and fetal primate cortical and trabecular bone specimens.

Antimony in drinking water, red blood cells, and serum: development of analytical methodology using transversely heated graphite furnace atomization-atomic absorption spectrometry.

An atomic absorption spectrometric (AAS) method has been developed for determining microg/L levels of Sb in samples of water and blood. The AAS method is based on the concept of stabilized temperature platform furnace atomization (STPF) realized through the use of a transversely heated graphite atomizer (THGA) furnace, longitudinal Zeeman-effect background correction, and matrix modification with palladium nitrate-magnesium nitrate-nitric acid. The method of standard additions is not mandatory. The detection limit (3 standard deviations of the blank) is 2.6 microg Sb/L for the water, red blood cells (RBCs), and serum samples. Data are presented on the degree of accuracy and precision. The THGA-AAS method is simple, fast, and contamination-free because the entire operation from sampling to AAS measurement is carried out in the same tube. The method has been applied to the determination of Sb in some leachate tap water samples derived from a static copper plumbing system containing Sn/Sb solders, and in small samples (0.5 ml) of RBCs and serum derived from rats given Sb-supplemented drinking water.