On the disintegration of cosmic ray nuclei by solar photons

We discuss in detail the possibility of observing pairs of simultaneous par allel air showers produced by the fragments of cosmic ray nuclei which disi ntegrated in collisions with solar photons. We consider scenarios with diff erent cosmic ray compositions, exploring the predicted rates for existing a nd planned detectors and looking for methods to extract information on the initial composition from the characteristics of the signal. In particular, we find that fluorescence detectors, such as HiRes or the Telescope Array, due to their low threshold (similar to 10(17) eV) and large area (similar t o 10(4) km(2)) may observe several events per year if cosmic rays at those energies are indeed heavy nuclei. The possibility of exploiting the angular orientation of the plane containing the two showers to further constrain t he cosmic ray composition is also discussed.