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Neoclassical transport in the helical reversed-field pinch
M Gobbin1, G Spizzo, L Marrelli
1Consorzio RFX, Euratom-ENEA Association, Corso Stati Uniti, 4 35127 Padova, Italy. marco.gobbin@igi.cnr.it
Physical Review Letters
|January 15, 2011
Summary
Test particle analysis reveals that helical reversed-field pinch (RFP) plasmas exhibit transport properties similar to stellarators. This finding supports the potential of helical RFPs as a viable fusion energy configuration.
Area of Science:
- Plasma Physics
- Fusion Energy Research
- Magnetic Confinement Fusion
Background:
- Reversed-field pinch (RFP) and stellarator configurations are leading approaches for magnetic confinement fusion.
- Understanding particle transport is crucial for achieving efficient fusion reactions.
- Previous studies suggested potential similarities between RFP and stellarator transport under specific conditions.
Purpose of the Study:
- To evaluate the diffusion coefficient of test particles in RFP plasmas that spontaneously develop helical shapes.
- To compare the transport characteristics of helical RFPs with those of stellarators.
- To assess the viability of helical RFPs as a fusion energy configuration.
Main Methods:
- Utilized test particle simulations to analyze diffusion coefficients.
- Investigated RFP plasma configurations exhibiting spontaneous helical deformation.
- Examined particle behavior at low collision frequencies and specific helical deformation levels (Bh/B=10%).
Main Results:
- Observed distinct similarities in diffusion coefficients between helical RFPs and stellarators.
- Found an almost complete absence of superbanana particles in experimentally relevant helical deformations.
- Demonstrated that transport in these helical RFPs is proportional to collision frequency at low collision rates.
- Ruled out transport inversely proportional to collision frequency, a characteristic of unoptimized stellarators.
Conclusions:
- Helical RFP configurations exhibit transport properties comparable to stellarators.
- The absence of superbanana particles and collision-frequency-proportional transport strengthen the case for helical RFPs.
- These findings enhance the prospects of helical RFPs as a promising direction for future fusion energy development.
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