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An Atmospheric Pressure Plasma Setup to Investigate the Reactive Species Formation
Published on: November 3, 2016
Measurement of pressure-gradient-driven currents in tokamak edge plasmas
D M Thomas1, A W Leonard, L L Lao
1General Atomics, PO Box 85608, San Diego, California 92186-5608, USA.
Physical Review Letters
|August 25, 2004
Summary
Localized currents in tokamak plasma edges are crucial for stability. Measurements reveal high current densities, challenging existing theories of edge plasma behavior and magnetic confinement.
Area of Science:
- Plasma Physics
- Fusion Energy Research
- Magnetohydrodynamics
Background:
- Localized currents driven by pressure gradients are critical for magnetohydrodynamic stability in toroidal plasma confinement.
- Understanding edge plasma currents is essential for achieving stable and efficient fusion energy.
Purpose of the Study:
- To measure current densities in the edge of L-mode and H-mode discharges on the DIII-D tokamak.
- To investigate the role of these currents in plasma stability and challenge existing theories.
Main Methods:
- Utilized the Zeeman effect in an injected lithium beam.
- Obtained high-resolution profiles of the poloidal magnetic field at the plasma edge.
Main Results:
- Measured current densities exceeding 1 MA/m² in a narrow (1-2 cm) region near the peak edge pressure gradient.
- Observed significant current densities in both L-mode and H-mode discharges.
Conclusions:
- The experimentally determined current densities are substantial enough to challenge current edge stability theories.
- These findings necessitate refinement of models describing current formation mechanisms in tokamak edge plasmas.
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