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Observation of odd toroidal Alfvén eigenmodes
G J Kramer1, S E Sharapov, R Nazikian
1Princeton Plasma Physics Laboratories, PO Box 451, Princeton, New Jersey 08543, USA. gkramer@pppl.gov
Physical Review Letters
|February 3, 2004
Summary
Researchers provide experimental evidence for the odd toroidicity induced Alfvén eigenmode (TAE) by observing both odd and even TAEs in Joint European Torus experiments. This finding confirms theoretical predictions of these plasma wave phenomena.
Area of Science:
- Plasma Physics
- Fusion Energy Research
- Magnetohydrodynamics
Background:
- Toroidicity Induced Alfvén Eigenmodes (TAEs) are important phenomena in magnetic confinement fusion.
- Previous research predicted the existence of odd-numbered TAEs, but experimental verification was lacking.
- Understanding TAEs is crucial for plasma stability and confinement in fusion devices.
Purpose of the Study:
- To present experimental evidence for the existence of the theoretically predicted odd toroidal Alfvén eigenmode (TAE).
- To identify and characterize odd TAEs by analyzing their properties in relation to even TAEs.
- To contribute to the understanding of Alfvén eigenmode behavior in fusion plasmas.
Main Methods:
- Utilizing the Joint European Torus (JET) tokamak.
- Creating low central magnetic shear plasmas using lower hybrid current drive.
- Generating a fast ion population with ion cyclotron heating.
- Analyzing the frequency, mode number, and timing of observed modes.
Main Results:
- Simultaneous observation of both odd and even TAEs in a normal shear discharge.
- Experimental confirmation of the existence of odd TAEs.
- Identification of odd TAEs based on their distinct characteristics compared to even TAEs.
Conclusions:
- The experimental results provide strong evidence for the existence of odd toroidal Alfvén eigenmodes.
- The findings validate theoretical predictions regarding odd TAEs.
- This study enhances the comprehension of Alfvén eigenmode dynamics in fusion plasmas.