Energetic Ion Transport and Concomitant Change of the Fusion Reactivity during Reconnection Events in Spherical Tori

Kolesnichenko, Ya.I. ; Lutsenko, V.V. ; White, R.B. ; Yakovenko, Yu.V.

Princeton University. Plasma Physics Laboratory.

关键词: Tail Ions;    Precession;    Energetic Ions;    Spherical Tori;    70 Plasma Physics And Fusion Technology;   

DOI  :  10.2172/828271
RP-ID  :  PPPL-3978
RP-ID  :  AC02-76CH03073
RP-ID  :  828271

美国|英语

来源: UNT Digital Library

【 摘 要 】

Effects of MHD reconnection events on the beam-plasma fusion reactivity and transport of the beam ions are studied. Based on the analysis of fusion reactivity changes induced by MHD events, the conclusion is drawn that the strong drops of the neutron yield during sawtooth crashes observed in the National Spherical Torus experiment (NSTX) [M. Ono et al., Nucl. Fusion 40, 557 (2000)] are associated with both a particle redistribution inside the plasma and a loss of the beam ions. Mechanisms of the energetic ion transport during sawtooth crashes are analyzed, in particular, with the use of the resonance adiabatic invariant derived in this paper. A numerical simulation of the particle motion during a sawtooth crash in NSTX is done with the code OFSEF [Ya. I. Kolesnichenko, et al., Nucl. Fusion 40, 1325 (2000)] extended for a better description of the particle precession. It is shown that the motion of toroidally passing particles in NSTX can become stochastic under the influence of a crash. This stochasticity, as well as the motion along the resonance island, leads to the escape of some particles from the plasma.