The modelling of the confinement of NBI deuterons in JET demonstrated a substantial effect of enhanced TF ripples on beam ion loss. Thus the introduction of a 50% additional N=16 TF ripple harmonic in JET leads to a 6-8 times increased loss of E > 40 keV NBI deuterons in monotonic current plasmas and enlarges the beam ion loss in current hole plasmas by a factor 14-15. The overlapping of regions of TF ripple and CH transport and hence their combined efficacy is found to result in an essential synergistic enhancement of beam ion loss. Partly thermalized deuterons are found to constitute the main contribution to the ripple induced loss of beam ions. Therefore the effect of enhanced TF ripples on the DD neutron yield is weaker when compared with the ripple induced reduction of the population of partly thermalized beam ions and especially, when compared to the reduction of trapped ion population which determines the neutral particle flux at mid-plane. The modelling results are in qualitative agreement with previous JET and TFTR observations. In the presence of current holes, the ripple effect on beam deuterons is predicted to be detectable by ~ 10-20% reduction of the beam-target DD neutron yield due to ripple loss of beam ions in envisaged JET experiments with enhanced ripples. However, the most pronounced effect of ripples may be observed in measurements of the ripple induced reduction of mid-plane neutral particle fluxes at energies in the tens keV range (neutral flux reduction expected to exceed that in the standard ripple case by 40-50%).
|Publication status||Published - 2006|
|Event||33rd European Physical Society Conference on Plasma Physics 2006, EPS 2006 - , Italy|
Duration: 1 Jan 2006 → …
|Conference||33rd European Physical Society Conference on Plasma Physics 2006, EPS 2006|
|Period||1/1/06 → …|
All Science Journal Classification (ASJC) codes
- Atomic and Molecular Physics, and Optics
Yavorskij, V., Goloborod'ko, V., Gorini, G., Kiptily, V., Parail, V., & Schoepf, K. (2006). Toroidal field ripple induced loss of neutral beam injection ions in JET. Paper presented at 33rd European Physical Society Conference on Plasma Physics 2006, EPS 2006, Italy.