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One of the most important ITER missions is to test tritium breeding blanket (TBB) concepts that would result in tritium self-sufficiency, an extraction of high grade heat and net electricity production in future fusion reactors. Knowledge of the TBB performance characteristics in the integrated fusion nuclear environment is essential to designing the TBB of the DEMO and the fusion reactor. Three equatorial ports in ITER are allotted for testing test blanket modules (TBMs), which are mock-ups of the TBB, allowing up to six TBMs to be simultaneously installed and tested - two TBMs per each port. Conceptual designs for all TBM systems are now completed, and the important next milestones are the achievement of the preliminary and the final design by 2025. The TBM systems will be installed during Assembly Phase III, which is planned to start in 2030, and tested during the ITER Pre-Fusion Power Operation 2, which is planned to start in 2032. This paper describes the objectives and management aspects of the TBM Program. Copyright © 2017 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

By an electromagnetic incompressible two-fluid model describing both ion temperature gradient drift modes (ηi modes) and resistive interchange modes (g modes), a new type of ηi mode is studied in cylindrical geometry including magnetic shear and an averaged curvature of Heliotron/Torsatron. This ηi mode is destabilized by the coupling to the unstable g mode. Finite plasma pressure beta increases the growth rate of this mode and the radial mode width also increases with plasma pressure beta indicating large anomalous transport in the Heliotron/Torsatron configuration. The transport from ηi mode exceeds that from resistive g when the mean-free-path exceeds the machine circumference. For plasma beta above two to three times the Suydam limit, the m=1/n=1 growth rate increases from the ηi mode value to the magnetohydrodynamic (MHD) value. [ABSTRACT FROM AUTHOR]

Numerical simulations of the ion-temperature-gradient-driven mode (ηi- mode) show that long-lived, large-scale coherent structures exist and play an important role in the study of the anomalous transport. In this work, the stationary solutions of the nonlinear equations describing the dynamics of the ηi -mode are investigated. The simplest solution is found to be a dipolar vortex in the shearless case. In the presence of the magnetic shear, a modified dipolar vortex solution is found through perturbation theory. [ABSTRACT FROM AUTHOR]

The effect of magnetic shear on the toroidal ion temperature gradient-driven drift mode is investigated through two-dimensional fluid simulations. Shear reduces the anomalous thermal transport by localizing the turbulence. Mixing length formulas for anomalous ion thermal transport are derived in various regimes with respect to the strength of the magnetic shear. [ABSTRACT FROM AUTHOR]

The electron thermal balance equation from the Braginskii equations with the finite Larmor radius heat flux is analyzed for the space-time-average power balance in the presence of electromagnetic fluctuations. Formulas for the anomalous thermal flux associated with the E×B motion and the magnetic δB⊥ fluctuations are derived and evaluated for the c/ωpe scale electromagnetic turbulence typical of the ∇Te-driven short wavelength drift modes. The result is compared with several Ohkawa-type formulas for the anomalous electron thermal energy transport. [ABSTRACT FROM AUTHOR]

The electron temperature gradient in tokamak geometry is shown to drive a short wavelength lower hybrid drift wave turbulence resulting from the unfavorable magnetic curvature on the outside of the toms. Ballooning mode theory is used to determine the stability regimes and the complex eigenfrequencies. At wavelengths of the order of the electron gyroradius, the polarization is electrostatic and the growth rate is greater than the electron transit time around the toms. At longer wavelengths of the order of the collisionless skin depth, the polarization is electromagnetic with electromagnetic vortices producing the dominant transport. The small scale electrostatic component of the turbulence produces a small, of order (m[sub e]/m[sub i])[sup ½], drift wave anomalous transport of both the trapped and passing electrons while the c/ω[sub pe] scale turbulence produces a neo-Alcator [Nucl. Fusion 25, 1127 (1985)] type transport from the stochastic diffusion of the trapped electrons. [ABSTRACT FROM AUTHOR]

Kinetic equations for the electromagnetic drift modes are derived and analyzed for the stability of tokamaks in the local approximation. In the dissipationless, hydrodynamic limit, the fifth-order polynomial dispersion relation previously studied is recovered. The kinetic velocity space integrals in the ion dynamics are shown to modify the five principal modes of oscillation and their polarizations. It is shown that in kinetic stability theory the critical plasma pressure defined in magnetohydrodynamic theory determines a transition from microinstability to macroinstability. [ABSTRACT FROM AUTHOR]