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Main-Ion Intrinsic Toroidal Rotation Profile Driven by Residual Stress Torque from Ion Temperature Gradient
B A Grierson1, W X Wang1, S Ethier1
1Princeton Plasma Physics Laboratory, Princeton University, Princeton, New Jersey 08543, USA.
Physical Review Letters
|January 21, 2017
Summary
Direct electron heating in tokamaks can alter deuterium ion rotation. Nonlinear simulations reveal that turbulence-driven residual stress shapes this hollow rotation profile, matching experimental data.
Area of Science:
- Plasma physics
- Fusion energy research
- Tokamak confinement
Background:
- Tokamak devices are crucial for fusion energy research.
- Understanding plasma rotation is key to stable fusion reactions.
- Previous studies suggested electron heating influences plasma rotation.
Purpose of the Study:
- To investigate the cause of intrinsic toroidal rotation profile changes in tokamak plasmas.
- To determine the role of electrostatic ion temperature gradient turbulence in shaping plasma rotation.
- To validate simulation predictions against experimental observations.
Main Methods:
- Utilizing the DIII-D tokamak for experimental measurements.
- Performing nonlinear gyrokinetic simulations to model plasma turbulence.
- Analyzing the momentum balance equation and residual stress in simulations.
Main Results:
- Observed a transition from flat to hollow toroidal rotation profiles in deuterium ions with increased electron heating.
- Simulations identified electrostatic ion temperature gradient turbulence as the source of residual stress.
- The simulated residual stress accurately predicted the location and structure of the hollow rotation profile.
Conclusions:
- Fluctuation-induced residual stress is a primary driver of intrinsic toroidal rotation in tokamaks.
- Nonlinear gyrokinetic simulations can quantitatively predict plasma rotation profiles.
- This finding advances the understanding of plasma dynamics in fusion devices.
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