Fast ion transport in the quasi-single helical reversed-field pinch
- Univ. of Wisconsin, Madison, WI (United States)
- Associazione Euratom-ENEA sulla Fusione, Padova (Italy). Consorzio RFX
- Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
- TAE Technologies Inc., Foothill Ranch, CA (United States)
The reversed-field pinch (RFP) can spontaneously transition from an axisymmetric magnetic topology to a 3D-helical geometry. Investigations on fast ion transport associated with energetic particle driven Alfvén instabilities, tearing mode induced stochasticity, and neoclassical effects have been performed on the Madison Symmetric Torus. STELLGAP produced shear-Alfvén continua seeded with V3FIT 3D-equilibrium reconstructions describe the response of Alfvénic bursting activity as a direct consequence of the equilibrium change on the fast ion resonance. Furthermore, far infrared interferometry resolved electron density perturbations associated with the bursts provide a spatial measurement of the mode structure and support the reconstructions. The bursts produce no global resonant fast ion transport; however, their disappearance at a high core-resonant amplitude implies other transport mechanisms at play. Additionally, neutral particle analysis and neutron signals suggest fast ion losses at sufficient core tearing mode strength, supporting the lack of Alfvénic activity. The guiding-center code ORBIT corroborates rapid fast ion loss times in the helical state largely as a consequence of remnant tearing modes. Additionally, ORBIT simulations demonstrate little neoclassical enhancement of particle transport. While superbanana orbits may exist, the growth in the core-resonant fast ion island and the associated secondary mode overlap govern the largest transport process, leading to robust fast ion losses in the 3D-RFP.
- Research Organization:
- Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
- Sponsoring Organization:
- USDOE Office of Science (SC), Fusion Energy Sciences (FES)
- Grant/Contract Number:
- AC05-00OR22725; FC02-05ER54814
- OSTI ID:
- 1648958
- Alternate ID(s):
- OSTI ID: 1511780
- Journal Information:
- Physics of Plasmas, Vol. 26, Issue 2; ISSN 1070-664X
- Publisher:
- American Institute of Physics (AIP)Copyright Statement
- Country of Publication:
- United States
- Language:
- English
Web of Science
Fast Ion Transport in the Three-Dimensional Reversed-Field Pinch
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journal | July 2019 |
Shear Alfvén wave continuum spectrum with bifurcated helical core equilibria
|
journal | September 2019 |
A measure of fast ion beta at marginal stability in the reversed field pinch
|
journal | June 2019 |
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