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2009
A set of key properties for an ideal dissipation scheme in gyrokinetic simulations is proposed, and implementation of a model collision operator satisfying these properties is described. This operator is based on the exact linearized test-particle collision operator, with approximations to the field-particle terms that preserve conservation laws an…
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2009
Large tokamaks capable of fusion power production such as ITER, should avoid large edge localized modes (ELMs), thought to be triggered by an ideal magnetohydrodynamic instability due to current at the plasma’s separatrix boundary. Unlike analytical work in a cylindrical approximation, numerical work finds the modes are stable. The plasma’s sep…
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2009
W sputtering during ICRF on ASDEX Upgrade (AUG) and temperature rise on JET A2 antenna septa are considered in connection with plasma conditions at the antenna plasma facing components and E|| near-fields. Large antenna-plasma clearance, high gas puff and low light impurity content are favorable to reduce W sputtering in AUG. The spatial distributi…
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2009
The possibility that electrons could be accelerated by inertial Alfvén waves to hard X-ray-emitting energies in the low solar corona during flares is investigated theoretically. This investigation is prompted in part by recent microwave observations indicating that the coronal magnetic field is strong enough that the Alfvén velocity c A above act…
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2009
Several types of microwave diagnostics, in the category of electron cyclotron emission (ECE) spectroscopy and reflectometry, have been developed on the Large Helical Device (LHD). Since LHD has a complicated magnetic configuration, the polarization effects have been studied for optimization of the microwave passive and active diagnostics. It was fo…
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2009
The stability of ion temperature gradient ITG modes and the quasilinear fluxes driven by them are analyzed in weakly collisional tokamak plasmas using a semianalytical model based on an approximate solution of the gyrokinetic equation, where collisions are modeled by a Lorentz operator. Although the frequencies and growth rates of ITG modes far fro…
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2009
The impact of edge localized modes (ELMs) carrying energies of up to 450 kJ on carbon erosion in the JET inner divertor is assessed by means of time resolved measurements using an in situ quartz microbalance diagnostic. The inner target erosion is strongly nonlinearly dependent on the ELM energy: a single 400 kJ ELM produces the same carbon erosion…
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2009
RF-sheath induced heat loads are identified from infrared thermography measurements on Tore Supra ITER-like prototype and JET A2 antennae, and are quantified by fitting thermal calculations. Using a simple scaling law assessed experimentally, the estimated heat fluxes are then extrapolated to the ITER ICRF launcher delivering 20MW RF power for seve…
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2009
We investigate drift kinetic effects on the resistive wall mode (RWM) stability in ITER plasmas, due to the mode resonance with magnetic precession drifts and/or bounce motion of bulk plasma thermal particles. A toroidal drift kinetic model is self-consistently incorporated into the MHD formulation. Self-consistent simulations using the hybrid kine…
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2009
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