Origin of C+ ions in the heliosphere

C+ pickup ions were investigated with the SWICS instrument along the trajectory of Ulysses, covering a broad range of solar latitude and distance. Whereas nearly all the observed H+ He+, N+, O+ and Ne+ pickup ions are created from the interstellar gas penetrating deep into the heliosphere, C+ comes primarily from an ''inner source'' which is located at a solar distance below a few AU and extends over all heliospheric latitudes investigated up to now. We present evidence that the C+ originates from carbon compounds evaporating from interstellar grains. This inner source also produces some O+ and N+ with estimated relative abundances 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 the order of 10(-3) as compared to the total production of O+ and N+ from 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 not be negligible.