Ulysses COSPIN observations of cosmic rays and solar energetic particles from the South Pole to the North Pole of the Sun during solar maximum

• Main Authors: Mckibben, R. B., Connell, J. J., Lopate, C., Zhang, M., Anglin, J. D., Balogh, A., Dalla, S., Sanderson, T. R., Marsden, R. G., Hofer, M. Y., Kunow, H., Posner, A., Heber, B.
• Other Authors: Institute for Study of Earth, Oceans and Space, University of New Hampshire (UNH), Florida Institute of Technology Melbourne, National Research Council of Canada (NRC), Blackett Laboratory, Imperial College London, Research and Scientific Support Department of ESA, Agence Spatiale Européenne = European Space Agency (ESA), Christian-Albrechts-Universität zu Kiel (CAU), Universität Osnabrück - Osnabrück University
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2003
• Subjects: [SDU.OCEAN]Sciences of the Universe [physics]/Ocean; Atmosphere; [SDU.STU]Sciences of the Universe [physics]/Earth Sciences; North Pole; South Pole; South pole
• Online Access: https://hal.science/hal-00317070; https://hal.science/hal-00317070/document; https://hal.science/hal-00317070/file/angeo-21-1217-2003.pdf

International audience In 2000?2001 Ulysses passed from the south to the north polar regions of the Sun in the inner heliosphere, providing a snapshot of the latitudinal structure of cosmic ray modulation and solar energetic particle populations during a period near solar maximum. Observations from the COSPIN suite of energetic charged particle telescopes show that latitude variations in the cosmic ray intensity in the inner heliosphere are nearly non-existent near solar maximum, whereas small but clear latitude gradients were observed during the similar phase of Ulysses' orbit near the 1994?95 solar minimum. At proton energies above ~10 MeV and extending up to >70 MeV, the intensities are often dominated by Solar Energetic Particles (SEPs) accelerated near the Sun in association with intense solar flares and large Coronal Mass Ejections (CMEs). At lower energies the particle intensities are almost constantly enhanced above background, most likely as a result of a mix of SEPs and particles accelerated by interplanetary shocks. Simultaneous high-latitude Ulysses and near-Earth observations show that most events that produce large flux increases near Earth also produce flux increases at Ulysses, even at the highest latitudes attained. Particle anisotropies during particle onsets at Ulysses are typically directed outwards from the Sun, suggesting either acceleration extending to high latitudes or efficient cross-field propagation somewhere inside the orbit of Ulysses. Both cosmic ray and SEP observations are consistent with highly efficient transport of energetic charged particles between the equatorial and polar regions and across the mean interplanetary magnetic fields in the inner heliosphere.