Cosmic-ray proton and helium spectra: results from the Jacee experiment

• Published in: The Astrophysical Journal
• Main Authors: Asakimori, K., Burnett, T. H., Cherry, M. L., Chevli, K., Christ, M. J., Dake, S., Derrickson, J. H., Fountain, W. F., Fuki, M., Gregory, J. C., Hayashi, T., Holynski, R., Iwai, J., Iyono, A., Johnson, J., Kodayashi, M., Lord, J., Miyamura, O., Moon, K. H., Nilsen, B. S., Ooa, H., Ogata, T., Olson, E. D., Parnell, T. A., Roberts, F. E., Sengupta, K., Shina, T., Strausz, S. C., Sugitate, T., Takahashi, Y., Tominaga, T., Watts, J. W., Wefel, J. P.
• Format: Text
• Language: unknown
• Published: LSU Digital Commons 1998
• Subjects: Acceleration of particles; Balloons; Ism: Cosmic rays; Antarctic; Antarc*
• Online Access: https://digitalcommons.lsu.edu/physics_astronomy_pubs/5526; https://doi.org/10.1086/305882

Measurements of the cosmic-ray hydrogen and helium spectra at energies from 20 to 800 TeV are presented. The experiments were performed on a series of twelve balloon flights, including several long duration Australia to South America and Antarctic circumpolar flights. No clear evidence is seen for a spectral break. Both the hydrogen and the helium spectra are consistent with power laws over the entire energy range, with integral spectral indices 1.80 ± 0.04 and 1.68-0.06+0.04 for the protons and helium, respectively. The results are fully consistent with expectations based on supernova shock acceleration coupled with a "leaky box" model of propagation through the Galaxy. © 1998. The American Astronomical Society. All rights reserved.