The Limit of Alpha Particles Orbit Calculation

The calculation of the single alpha particle orbit in a background of thermalized plasma is fundamentally transparent and leads often to a simple physical interpretation. However, for certain tasks, like those including also statistics on random events, these calculations can be excessively time consuming, even for large computers. These tasks are best suited for calculations including statistical operators which, however, often require the simplification of the model, leaving off for example, the space dependence of the plasma parameters. As the fast fusion products have relatively large Larmor radii and their guiding centers may have large excursions in a possibly inhomogeneous plasma, such a simplification may produce misleading results. Therefore, it may be necessary to turn back to orbit calculations. In this paper, we will give the results of several cases at the frontier between orbit and statistical operator calculations: (1) The burn up of fusion produced tritium in the ohmic FT (theory and experiment). (2) The hot spots of 3He wall loading due to magnetic ripple (computational study). (3) Slow down of α with ripple resonance (computational study).