Effects of toroidal field ripple on suprathermal ions in tokamak plasmas
Analytic calculations of three important effects of toroidal field ripple on suprathermal ions in tokamak plasmas are presented. In the first process, collisional ripple-trapping, beam ions become trapped in local magnetic wells near their banana tips due to pitch-angle scattering as they traverse the ripple on barely unripple-trapped orbits. In the second process, collisionless ripple-trapping, near-perpendicular untrapped ions are captured (again near a banana tip) due to their finite orbits, which carry them out into regions of higher ripple. In the third process, banana-drift diffusion, fast-ion banana orbits fail to close precisely, due to a ripple-induced variable lingering period near the banana tips. These three mechanisms lead to substantial radial transport of banana-trapped, neutral-beam-injected ions when the quantity ..cap alpha..* identical with epsilon/sin theta/Nqdelta is of order unity or smaller.
- Research Organization:
- Princeton Plasma Physics Lab. (PPPL), Princeton, NJ (United States)
- DOE Contract Number:
- EY-76-C-02-3073
- OSTI ID:
- 5634416
- Report Number(s):
- PPPL-1637; TRN: 80-005456
- Country of Publication:
- United States
- Language:
- English
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TOKAMAK DEVICES
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PLASMA CONFINEMENT
BANANA REGIME
NEUTRAL ATOM BEAM INJECTION
ORBITS
TRANSPORT THEORY
TRAPPING
BEAM INJECTION
CLOSED PLASMA DEVICES
CONFINEMENT
MAGNETIC FIELD CONFIGURATIONS
THERMONUCLEAR DEVICES
700105* - Fusion Energy- Plasma Research- Plasma Kinetics-Theoretical- (-1987)