Evidence for emission of cosmic rays by jupiter

Cosmic ray data obtained with a world neutron monitor network have been analyzed with the purpose to investigate whether Jupiter is a cosmic ray source. The data cover the period 1961 through 1965 for stations with cutoff energy above 6.3 GeV. Strong evidence is found that the cosmic ray flux is about 1% larger when the Earth is passing across the interplanetary magnetic field line intersecting the Jupiter orbit.