4.5 Article

Visualization of fast ion phase-space flow in plasmas well-below, near and well-above Alfven eigenmode stability threshold in tokamak

Related references

Note: Only part of the references are listed.
Article Physics, Fluids & Plasmas

Orbit tomography of energetic particle distribution functions

L. Stagner et al.

Summary: Both fast ions and runaway electrons are crucial for future fusion devices. However, current diagnostics can only detect a limited range of the energetic particle phase-space, limiting the accuracy of model validation. This study introduces orbit tomography, a method that can reconstruct the 3D phase-space distribution of all energetic particle orbits in the plasma, using orbit weight functions. The technique is validated by reconstructing the fast-ion distribution function of an MHD-quiescent DIII-D discharge and studying the redistribution of fast ions during a sawtooth crash at ASDEX upgrade.

NUCLEAR FUSION (2022)

Article Physics, Fluids & Plasmas

Theoretical studies of low-frequency Alfven modes in tokamak plasmas

Ruirui Ma et al.

Summary: This study theoretically investigates the linear wave properties of low-frequency Alfven modes (LFAMs) observed in DIII-D tokamak experiments and finds that LFAM is a reactive-type kinetic ballooning mode instability under certain experimental conditions. The study also explains the observed spectral patterns and the dependence of instability drive on electron temperature in the experiments.

PLASMA PHYSICS AND CONTROLLED FUSION (2022)

Article Physics, Fluids & Plasmas

Modelling the Alfv ′en eigenmode induced fast-ion flow measured by an imaging neutral particle analyzer

J. Gonzalez-Martin et al.

Summary: An imaging neutral particle analyzer (INPA) was used to diagnose fast-ion flow driven by multiple marginally unstable Alfv ’en eigenmodes (AEs) in the DIII-D tokamak. Traditional energetic particle diffusivity modeling failed to interpret the observed fast ion depletion, while self-consistent multi-phase hybrid simulations were able to reproduce most features of the observed phase-space flow.

NUCLEAR FUSION (2022)

Article Physics, Fluids & Plasmas

'BAAE' instabilities observed without fast ion drive

W. W. Heidbrink et al.

Summary: The experiment found that the LFMs occur in plasmas with high electron temperature and modest beta, and are related to rational values near the minimum safety factor q(min).

NUCLEAR FUSION (2021)

Article Physics, Multidisciplinary

Visualization of Fast Ion Phase-Space Flow Driven by Alfven Instabilities

X. D. Du et al.

Summary: In the DIII-D tokamak, fast ion phase-space flow driven by Alfven eigenmodes (AEs) exhibits different trajectories in different regions and is influenced by energy. The flow trajectories in phase space align with the intersection lines of constant magnetic moment and constant E-(omega/n)P-zeta surfaces, indicating large-scale phase-space transport of fast ions at those points. This destructive flow behavior of fast ions is consistent with nonlinear hybrid kinetic-magnetohydrodynamics simulation, where ions transition between different flow trajectories for phase-space transport.

PHYSICAL REVIEW LETTERS (2021)

Article Physics, Fluids & Plasmas

Beam modulation and bump-on-tail effects on Alfven eigenmode stability in DIII-D

M. A. Van Zeeland et al.

Summary: The recent DIII-D experiment investigated the effects of beam modulation on Alfven eigenmode stability, finding that variations in modulation period can impact the beam driven Alfven eigenmode spectrum and fast ion transport. Changing the modulation period altered the activity of core modes from reversed shear Alfven eigenmodes to a mix of RSAE and beta-induced Alfven eigenmodes. The observed TAE modulation with interleaved beams is likely a result of pitch angle dependence combined with the slowing down of the tangential beam between pulses.

NUCLEAR FUSION (2021)

Article Physics, Fluids & Plasmas

Gyrokinetic simulation of low-frequency Alfvenic modes in DIII-D tokamak

G. J. Choi et al.

Summary: Global gyrokinetic simulations have found a beta-induced Alfven eigenmode and a low-frequency mode co-existing in the DIII-D tokamak experiments. The low-frequency mode can be excited without fast ions, has a structure consistent with experimental observations, and is not the conventional Alfven-acoustic eigenmode as shown by an antenna scan. The simulated mode structures and parametric dependencies are in agreement with experimental findings.

NUCLEAR FUSION (2021)

Article Physics, Multidisciplinary

Multiscale Chirping Modes Driven by Thermal Ions in a Plasma with Reactor-Relevant Ion Temperature

X. D. Du et al.

Summary: The study observed a thermal ion driven bursting instability with rapid frequency chirping, attributed to an Alfvenic ion temperature gradient mode, in the DIII-D tokamak. This mode can lead to changes in magnetic topology at the plasma edge and potentially cause minor disruption events.

PHYSICAL REVIEW LETTERS (2021)

Article Physics, Fluids & Plasmas

Resolving the fast ion distribution from imaging neutral particle analyzer measurements

X. D. Du et al.

NUCLEAR FUSION (2020)

Article Instruments & Instrumentation

Imaging Neutral Particle Analyzer (INPA) measurements of confined fast ions in DIII-D

M. A. Van Zeeland et al.

JOURNAL OF INSTRUMENTATION (2019)

Article Physics, Fluids & Plasmas

Dynamic neutral beam current and voltage control to improve beam efficacy in tokamaks

D. C. Pace et al.

PHYSICS OF PLASMAS (2018)

Article Physics, Multidisciplinary

Suppression of Alfven Modes on the National Spherical Torus Experiment Upgrade with Outboard Beam Injection

E. D. Fredrickson et al.

PHYSICAL REVIEW LETTERS (2017)

Article Physics, Fluids & Plasmas

Fast-ion transport by Alfven eigenmodes above a critical gradient threshold

W. W. Heidbrink et al.

PHYSICS OF PLASMAS (2017)

Review Physics, Fluids & Plasmas

Energetic particles in spherical tokamak plasmas

K. G. McClements et al.

PLASMA PHYSICS AND CONTROLLED FUSION (2017)

Article Physics, Fluids & Plasmas

Interpretation of fast-ion signals during beam modulation experiments

W. W. Heidbrink et al.

NUCLEAR FUSION (2016)

Article Physics, Multidisciplinary

Observation of Critical-Gradient Behavior in Alfven-Eigenmode-Induced Fast-Ion Transport

C. S. Collins et al.

PHYSICAL REVIEW LETTERS (2016)

Article Physics, Multidisciplinary

Resistive Interchange Modes Destabilized by Helically Trapped Energetic Ions in a Helical Plasma

X. D. Du et al.

PHYSICAL REVIEW LETTERS (2015)

Review Physics, Fluids & Plasmas

Self-organized criticality and the dynamics of near-marginal turbulent transport in magnetically confined fusion plasmas

R. Sanchez et al.

PLASMA PHYSICS AND CONTROLLED FUSION (2015)

Article Computer Science, Interdisciplinary Applications

ASCOT: Solving the kinetic equation of minority particle species in tokamak plasmas

E. Hirvijoki et al.

COMPUTER PHYSICS COMMUNICATIONS (2014)

Review Physics, Fluids & Plasmas

Energetic particle physics in fusion research in preparation for burning plasma experiments

N. N. Gorelenkov et al.

NUCLEAR FUSION (2014)

Article Physics, Multidisciplinary

Radial Localization of Toroidicity-Induced Alfven Eigenmodes

Zhixuan Wang et al.

PHYSICAL REVIEW LETTERS (2013)

Article Physics, Mathematical

A Code that Simulates Fast-Ion Dα and Neutral Particle Measurements

W. W. Heidbrink et al.

COMMUNICATIONS IN COMPUTATIONAL PHYSICS (2011)

Article Physics, Fluids & Plasmas

Energetic-ion-driven global instabilities in stellarator/helical plasmas and comparison with tokamak plasmas

K. Toi et al.

PLASMA PHYSICS AND CONTROLLED FUSION (2011)

Article Physics, Fluids & Plasmas

Major minority: energetic particles in fusion plasmas

B. N. Breizman et al.

PLASMA PHYSICS AND CONTROLLED FUSION (2011)

Article Physics, Fluids & Plasmas

Perturbative studies of transport phenomena in fusion devices

F. Ryter et al.

PLASMA PHYSICS AND CONTROLLED FUSION (2010)

Article Physics, Fluids & Plasmas

Excitation of Alfven eigenmodes by low energy beam ions in the DIII-D and JET tokamaks

R. Nazikian et al.

PHYSICS OF PLASMAS (2008)

Article Physics, Multidisciplinary

Anomalous flattening of the fast-ion profile during Alfven-eigenmode activity

W. W. Heidbrink et al.

PHYSICAL REVIEW LETTERS (2007)

Article Physics, Fluids & Plasmas

Measurements of fast-ion acceleration at cyclotron harmonics using Balmer-alpha spectroscopy

W. W. Heidbrink et al.

PLASMA PHYSICS AND CONTROLLED FUSION (2007)

Review Physics, Fluids & Plasmas

Chapter 5: Physics of energetic ions

A. Fasoli et al.

NUCLEAR FUSION (2007)

Article Physics, Multidisciplinary

Radial structure of Alfven eigenmodes in the DIII-D tokamak through electron-cyclotron-emission measurements

M. A. Van Zeeland et al.

PHYSICAL REVIEW LETTERS (2006)

Letter Physics, Fluids & Plasmas

Alfven eigenmode observations on DIII-D via two-colour CO2 interferometry

MA Van Zeeland et al.

PLASMA PHYSICS AND CONTROLLED FUSION (2005)

Article Computer Science, Interdisciplinary Applications

The tokamak Monte Carlo fast ion module NUBEAM in the National Transport Code Collaboration library

A Pankin et al.

COMPUTER PHYSICS COMMUNICATIONS (2004)

Article Instruments & Instrumentation

Electron cyclotron emission radiometer upgrade on the DIII-D tokamak

ME Austin et al.

REVIEW OF SCIENTIFIC INSTRUMENTS (2003)