In tokamak discharges, toroidal Alfvén eigenmodes often experience complex semi-periodic frequency modulation known as chirping. These events modify the local high energy particle distribution and are expected to occur in many future fusion devices, which include energetic beams or fusion products. This paper presents a study of simulations of mode chirping made in order to better understand its phase-space properties in a realistic tokamak configuration. We find a mechanism that permits rapid repeated chirping with strong amplitude variation in each chirp. Each chirp is associated with an amplitude crash to low magnitude and local manipulation of the density gradients through a shift of mode phase through π. The chirping produces high density clumps, which propagate down the fast ion density gradient and low density holes that propagate up the density gradient away from the resonance. This flow of particles across the resonance provides an energy source and local gradients for repeated chirping.
Skip Nav Destination
Article navigation
Research Article|
May 28 2020
Phase-space dynamics of Alfvén mode chirping
R. B. White
;
R. B. White
a)
Princeton Plasma Physics Laboratory, Princeton University
, Princeton, New Jersey 08543, USA
a)Author to whom correspondence should be addressed: [email protected]
Search for other works by this author on:
V. N. Duarte
;
V. N. Duarte
Princeton Plasma Physics Laboratory, Princeton University
, Princeton, New Jersey 08543, USA
Search for other works by this author on:
N. N. Gorelenkov
;
N. N. Gorelenkov
Princeton Plasma Physics Laboratory, Princeton University
, Princeton, New Jersey 08543, USA
Search for other works by this author on:
E. D. Fredrickson
;
E. D. Fredrickson
Princeton Plasma Physics Laboratory, Princeton University
, Princeton, New Jersey 08543, USA
Search for other works by this author on:
M. Podesta
M. Podesta
Princeton Plasma Physics Laboratory, Princeton University
, Princeton, New Jersey 08543, USA
Search for other works by this author on:
a)Author to whom correspondence should be addressed: [email protected]
Phys. Plasmas 27, 052108 (2020)
Article history
Received:
February 14 2020
Accepted:
May 05 2020
Citation
R. B. White, V. N. Duarte, N. N. Gorelenkov, E. D. Fredrickson, M. Podesta; Phase-space dynamics of Alfvén mode chirping. Phys. Plasmas 1 May 2020; 27 (5): 052108. https://doi.org/10.1063/5.0004610
Download citation file:
Pay-Per-View Access
$40.00
Sign In
You could not be signed in. Please check your credentials and make sure you have an active account and try again.
Citing articles via
Progress toward fusion energy breakeven and gain as measured against the Lawson criterion
Samuel E. Wurzel, Scott C. Hsu
Weakly nonlinear incompressible Rayleigh–Taylor–Kelvin–Helmholtz instability in plane geometry
Zhen-Qi Zou, Jun-Feng Wu, et al.
Related Content
Modeling of chirping toroidal Alfvén eigenmodes in NSTX
Phys. Plasmas (September 2019)
Orbit-based analysis of nonlinear energetic ion dynamics in tokamaks. II. Mechanisms for rapid chirping and convective amplification
Phys. Plasmas (April 2016)
Orbit-based analysis of nonlinear energetic ion dynamics in tokamaks. I. Effective mode number profile and resonant frequency tracking
Phys. Plasmas (April 2016)
Simulation of Alfvénic avalanche onset in NSTX
Phys. Plasmas (February 2020)
Destabilization of toroidal Alfvén eigenmode during neutral beam injection heating on HL-2A
Phys. Plasmas (April 2017)