Fast-ion orbit effects during ion cyclotron range of frequency experiments on the Princeton Large Torus

The angular dependence of the flux of fast neutrals was measured in conjunction with Ion Cyclotron Range of Frequency experiments on the Princeton Large Torus. A regime was found where the energetic tail of the charge-exchange neutral flux was strongly anisotropic. Unexpectedly, however, the flux from co-going ions was peaked at an angle intermediate between perpendicular and parallel. This could be the consequence of a preferential filling of that class of banana orbits whose tips are located within the ion cyclotron resonance layer.