Turbulent transport of alpha particles in reactor plasmas

Estrada-Mila, C.; Candy, J.; Waltz, R. E.

doi:doi:10.1063/1.2364149

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Obliquely propagating ion acoustic solitary waves in a dusty plasma in the presence of an external magnetic field

The obliquely propagating nonlinear ion acoustic wave in a dusty plasma subjected to an external magnetic field is studied in the Sagdeev’s pseudopotential framework. The Sagdeev’s potential is derived in two cases, one of which assumes the quasineutrality condition and the other uses the Poisson equation instead. The respective ranges of parameters for which solitary waves exist in both the cases are studied in some detail numerically.

Relativistically intense plane electromagnetic waves in electron–positron plasmas: Nonlinear self-modulation and harmonics generation regimes

A fully nonlinear one-dimensional problem describing the interactions of relativistically intense plane electromagnetic waves and cold locally non-neutral electron–positron plasmas is derived from Maxwell and fluid dynamics equations. Numerical and asymptotic solutions to this problem for phase velocities close to the speed of light are presented. Depending on the magnitude of the plasma longitudinal electric-field potential, the system considered is found to support two distinct regimes of pla...

A systematic study of the behavior of energetic ions in reactor plasmas is presented. Using self-consistent gyrokinetic simulations, in concert with an analytic asymptotic theory, it is found that alpha particles can interact significantly with core ion-temperature-gradient turbulence. Specifically, the per-particle flux of energetic alphas is comparable to the per-particle flux of thermal species (deuterium or helium ash). This finding opposes the conventional wisdom that energetic ions, because of their large gyroradii, do not interact with the turbulence. For the parameters studied, a turbulent modification of the alpha-particle density profile appears to be stronger than turbulent modification of the alpha-particle pressure profile. Crude estimates indicate that the alpha density modification, which is directly proportional to the core turbulence intensity, could be in the range of 15% at midradius in a reactor. The corresponding modification of the alpha-particle pressure profile is predicted to be smaller (in the 1% range).

Article Outline

INTRODUCTION AND SUMMARY
ALPHA PARTICLE PHYSICS
1. Slowing-down form of the alpha particle distribution
2. An equivalent alpha-particle Maxwellian
3. Alpha particle profiles in ITER
SIMULATION UNITS AND CONVENTIONS
GYRO SIMULATIONS
1. Nonlinear temperature scan: Basic properties
2. Nonlinear temperature scan: Alphas (η_α = 0.1)
3. Nonlinear temperature scan: Helium ash (η_α = 3.0)
4. Quasilinear GYRO scans
THEORETICAL ANALYSIS
1. Linear and quasilinear gyrokinetic theory
2. Helium pinch theory
3. Formulas for turbulence decay at high energies
DISCUSSION OF RESULTS
1. General features
2. Implications for alpha confinement
3. Alpha profile modification estimates
CONCLUSIONS

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KEYWORDS and PACS

Keywords

plasma transport processes, fusion reactor theory, plasma turbulence, plasma simulation, plasma kinetic theory, plasma temperature, plasma density, plasma pressure, Tokamak devices, plasma toroidal confinement

PACS

52.25.Fi

Transport properties
52.25.Vy

Impurities in plasmas
52.30.−q
52.35.Bj

Magnetohydrodynamic waves (e.g., Alfven waves)
52.55.Pi

Fusion products effects (e.g., alpha-particles, etc.), fast particle effects

ARTICLE DATA

Digital Object Identifier

http://dx.doi.org/10.1063/1.2364149

PUBLICATION DATA

ISSN

1070-664X (print)

1089-7674 (online)

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$abstract.society.value is a Member of CrossRef

American Institute of Physics

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