Abstract
Numerical solutions of the cosmic-ray transport equation for the interplanetary region and including the effects of diffusion, convection, and energy loss, have been obtained for a galactic differential number-density spectrum of gaussian form, central kinetic energyT 0, and a width at half height maximum of 0.1T 0. These solutions have been used to show the redistribution in energy, and the reduction in number density, within the solar cavity. The mean energy loss is shown to be usefully approximated by the force-field potential Φ when Φ/T 0≲1/2. The principal finding is that galactic cosmic-ray protons and helium nuclei, with kinetic energies less than about 80 MeV/nucleon, virtually, are completely excluded from near Earth by convective effects. As a result of this exclusion, it is found that it is not possible to demodulate the proton and helium-nuclei spectra, observed in 1964–65, to obtain information about low-energy galactic cosmic rays.
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Bleeker, J. A. M., Burger, J. J., Deerenberg, A. J. M., Scheepmaker, A., Swanenburg, B. N., and Tanaka, Y.: 1968,Can. J. Phys. 46, S522.
Coleman, P. J.: 1966,J. Geophys. Res. 71, 5509.
Diaz, J. B.: 1958,Handbook of Automation, Computation and Control (Ed. by E. M. Grabbe, S. Ramo, and D. E. Wooldridge), John Wiley and Sons, New York.
Earl, J. A., Neely, D. E., and Rygg, T. A.: 1970,Univ. of Md. Tech. Rept. 70-076.
Fanselow, J. L., Hartman, R. C., Hildebrand, R. H., and Meyer, P.: 1969,Astrophys. J. 158, 771.
Fisk, L. A.: 1969, Ph.D. Thesis, University of California.
Fisk, L. A.: 1971,J. Geophys. Res. Letters 76, 221.
Fisk, L. A. and Axford, W. I.: 1969,J. Geophys. Res. 74, 4973.
Fisk, L. A., Gleeson, L. J., and Axford, W. I.: 1969,Proc. 11th Int. Conf. on Cosmic Rays, Budapest, 1969 (in press).
Gleeson, L. J. and Axford, W. I.: 1967,Astrophys. J. 149, L115.
Gleeson, L. J. and Axford, W. I.: 1968a,Can. J. Phys. 46, S937.
Gleeson, L. J. and Axford, W. I.: 1968b,Astrophys. J. 154, 1011.
Gleeson, L. J. and Axford, W. I.: 1969,Astrophys. Space Sci. 2, 431.
Gleeson, L. J. and Urch, I. H.: 1970,J. Geophys. Res. Letters (in press).
Gloeckler, G. and Jokipii, J. R.: 1967,Astrophys. J. 148, L41.
Goldstein, M. L., Fisk, L. A., and Ramaty, R.: 1970a,Phys. Rev. Letters 25, 832.
Goldstein, M. L., Ramaty, R., and Fisk, L. A.: 1970b,Phys. Rev. Letters 24, 1193.
Jokipii, J. R.: 1967,Astrophys. J. 149, 405.
Jokipii, J. R. and Coleman, P. J., Jr.: 1968,J. Geophys. Res. 73, 5495.
Jokipii, J. R. and Parker, E. N.: 1967,Planetary Space Sci. 15, 1375.
Jokipii, J. R. and Parker, E. N.: 1970,Astrophys. J. 160, 735.
Lezniak, J. A. and Webber, W. R.: 1970,J. Geophys. Res. (in press).
L'Heureux J. and Meyer, P.: 1968,Can. J. Phys. 46, S892.
Parker, E. N.: 1965,Planetary Space Sci. 13, 9.
Parker, E. N.: 1966,Planetary Space Sci. 14, 371.
Sari, J. W. and Ness, N. F.: 1969,Solar Phys. 8, 155.
Siscoe, G. L., Davis, L., Jr., Coleman, P. J., Jr., Smith, E. J., and Jones, D. E.: 1968,J. Geophys. Res. 73, 61.
Webber, W. R.: 1968,Australian J. Phys. 21, 845.
Webber, W. R.: 1969, Survey-paper given at theSeminar on the Study of Interplanetary Space Physics by means of Cosmic Rays, Leningrad, U.S.S.R., June 4–7, 1969.
Webber, W. R. and Chotkowski, C.: 1967,J. Geophys. Res. 72, 2783.
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Gleeson, L.J., Urch, I.H. Energy losses and modulation of galactic cosmic rays. Astrophys Space Sci 11, 288–308 (1971). https://doi.org/10.1007/BF00661360
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DOI: https://doi.org/10.1007/BF00661360