Resonant wave-particle interactions modified by intrinsic Alfvénic turbulence

2012 ◽  
Vol 19 (8) ◽  
pp. 082902 ◽  
Author(s):  
C. S. Wu ◽  
C. B. Wang ◽  
D. J. Wu ◽  
K. H. Lee
Keyword(s):  
Particle Interactions ◽  
Resonant Wave ◽  
Wave Particle Interactions

Banded structures in electron pitch angle diffusion coefficients from resonant wave-particle interactions

2016 ◽  
Vol 23 (4) ◽  
pp. 042101 ◽  
Author(s):  
A. K. Tripathi ◽  
R. P. Singhal ◽  
G. V. Khazanov ◽  
L. A. Avanov
Keyword(s):  
Diffusion Coefficients ◽  
Pitch Angle ◽  
Particle Interactions ◽  
Resonant Wave ◽  
Wave Particle Interactions

Collisional broadening of nonlinear resonant wave–particle interactions

2021 ◽  
Vol 87 (6) ◽  
Author(s):  
Peter J. Catto ◽  
Elizabeth A. Tolman
Keyword(s):  
Boundary Layers ◽  
Alpha Particle ◽  
General Procedure ◽  
Nonlinear Effects ◽  
Particle Energy ◽  
Current Drive ◽  
Particle Interactions ◽  
Resonant Wave ◽  
Order Of Magnitude ◽  
Wave Particle Interactions

A general procedure for understanding plasma behaviour when resonant wave–particle interactions are the sole destabilizing and transport mechanism or only heating and/or current drive source is highlighted without recourse to involved numerical or analytical treatments. These phenomena are characterized by transport that appears to be collisionless even though collisions play a central role in narrow collisional boundary layers. The order of magnitude estimates, which include nonlinear effects, are shown to provide expressions in agreement with the principal results of recent toroidal Alfvén eigenmode (TAE), toroidal magnetic field ripple, and heating and current drive treatments. More importantly, the retention of nonlinearities leads to new estimates of the alpha particle energy diffusivity at saturation for TAE modes, and the ripple threshold at which superbanana plateau evaluations of alpha particle transport are modified by nonlinear radial drift effects. In addition, the estimates indicate when quasilinear descriptions for heating and current drive will begin to fail. The phenomenological procedure demonstrates that in magnetic fusion relevant plasmas, narrow collisional boundary layers must be retained for resonant wave–particle interactions as they enhance the role of collisions, and make stochastic particle motion unlikely to be more important than other nonlinear processes.

Statistical EMIC diffusion models calculated by averaging observation specific diffusion coefficients

2021 ◽  
Author(s):  
Johnathan Ross ◽  
Sarah Glauert ◽  
Richard Horne ◽  
Nigel Meredith ◽  
Clare Watt
Keyword(s):  
Diffusion Coefficients ◽  
Radiation Belt ◽  
Diffusion Models ◽  
Relativistic Electrons ◽  
Particle Interactions ◽  
Resonant Wave ◽  
Van Allen Probes ◽  
Through Diffusion ◽  
Wave Particle Interactions ◽  
Emic Waves

<p>Electromagnetic ion cyclotron (EMIC) waves play an important role in relativistic electron losses in the radiation belts through diffusion via resonant wave-particle interactions. We present a new statistical model of electron diffusion by EMIC waves calculated, using Van Allen Probe observations, by averaging observation specific diffusion coefficients. The resulting diffusion coefficients therefore capture a wider range of wave-particle interactions than previous average models which are calculated using average observations. These calculations, and their role in radiation belt simulations, are then compared against existing diffusion models. The new diffusion coefficients are found to significantly improve the agreement between the calculated decay of relativistic electrons and Van Allen Probes data.</p><p> </p>

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