Fast ion loss and radial electric field in Wendelstein 7-A stellarator
Abstract
A theoretical model is developed to determine the radial electric field and the fast ion loss simultaneously in stellarators, and is applied to the Wendelstein 7-A stellarator. The predicted value of the radial electric field is more closer to experiments than the purely neoclassical calculation. The loss rate, which is determined simultaneously, is in the range of experimental observations. The partition of the injection energy by the bulk heating, direct orbit loss, and shine through is estimated by using the self consistent electric field profile. The orbit loss becomes noticeable as the injection energy increases. The influence of the neutral particles is also studied. Neutral particles enhances the negative radial electric field, and reduces the direct orbit loss by the expense of the charge exchange loss. The impact of the increased radial electric field on the neoclassical ion thermal energy loss is compared to the direct loss of fast ions. The reduction of the neoclassical loss is much smaller than the orbit loss.
- Publication:
-
Unknown
- Pub Date:
- October 1991
- Bibcode:
- 1991filr.rept.....I
- Keywords:
-
- Controlled Fusion;
- Electric Fields;
- Energy Dissipation;
- Ions;
- Mathematical Models;
- Plasma Control;
- Radial Distribution;
- Stellarators;
- Charge Exchange;
- Estimating;
- Injection;
- Neutral Particles;
- Plasma Heating;
- Self Consistent Fields;
- Thermal Energy;
- Plasma Physics