ORIGIN OF C+ IONS IN THE HELIOSPHERE

C+ pickup ions were investigated with the SWICS instrument along the t rajectory of Ulysses, covering a broad range of solar latitude and dis tance. Whereas nearly all the observed H+ He+, N+, O+ and Ne+ pickup i ons are created from the interstellar gas penetrating deep into the he liosphere, C+ comes primarily from an ''inner source'' which is locate d at a solar distance below a few AU and extends over all heliospheric latitudes investigated up to now. We present evidence that the C+ ori ginates from carbon compounds evaporating from interstellar grains. Th is inner source also produces some O+ and N+ with estimated relative a bundances of C+/O+ similar to 1 and N+/O+ similar to 0.2. However, the total amount of O+ and N+ produced by this inner source is only of th e order of 10(-3) as compared to the total production of O+ and N+ fro m the interstellar gas in the heliosphere, respectively Thus the inner source does not significantly contribute to oxygen or nitrogen in the anomalous cosmic rays (ACR) but its contribution to ACR-carbon may no t be negligible.