Abstract
A series of geomagnetic disturbances and cosmic ray variations caused by the McMath plage region 8818 in the latter half of May 1967 were examined. The systematic changes of the geomagnetic disturbances were observed as the relative location between the responsible flares and the earth changed during the half solar rotation period.
The storm of May 25/26, 1967 was then studied in great detail on the basis of records from a number of magnetic and cosmic ray observatories. A large asymmetric main phase field in mid-and low-latitude regions (and thus an asymmetric ring current belt) grew rapidly during the first three successive polar magnetic substorms. The cosmic ray intensity variations during the storm consisted of the Forbush decrease and the ring current effect. The Forbush decrease had a marked north-south asymmetry during its developing phase.
Similar content being viewed by others
References
Akasofu, S.-I. and Chapman, S.: 1960, ‘Some Features of the Magnetic Storms of July 1959, and Tentative Interpretations’, UGGI Monograph 7, 93–108.
Akasofu, S.-I. and Chapman, S.: 1963, ‘The Lower Limit of Latitude (U.S. Sector) of Northern Quiet Auroral Arcs, and its Relation to Dst (H)’, J. Atmosph. Terrest. Phys. 25, 9–12.
Akasofu, S.-I. and Chapman, S.: 1967, ‘A Systematic Shift of the DS Axis’, Planetary Space Sci. 15, 937–938.
Akasofu, S.-I. and Yoshida, S.: 1967, ‘The Structure of the Solar Plasma Flow Generated by Solar Flares’, Planetary Space Sci. 15, 39–47.
Akasofu, S.-I. and Perreault, P. D.: 1969, ‘The Geomagnetic Storm of May 25/26, 1967’, Rept. UAG-3, World Data Center A, ESSA, Boulder, Colorado.
Cahill, L. J.: 1966, ‘Inflation of the Inner Magnetosphere During a Magnetic Storm’, J. Geophys. Res. 71, 4505–4519.
Castelli, J. P., Aarons, J., and Michael, G. A.: ‘Flux Density Measurements of Radio Bursts of Proton-Producing Flares and Nonproton Flares’, J. Geophys. Res. 72, 5491–5498.
Chapman, S.: 1952, ‘The Morphology of Geomagnetic Storms: An Extension of the Analyses of DS, the Disturbance Local-Time Inequality’, Ann. Geofis. 5, 481–499.
Cummings, D. W. and Coleman, Jr., P. J.: 1968, ‘Simultaneous Magnetic Field Variation at the Earth's Surface and at Synchronous, Equatorial Distance, Part 1: Bay-Associated Events’, Radio Sci. 3, 758–761.
Davis, T. N. and Sugiura, M.: 1966, ‘Auroral Electrojet Activity Index AE and Its Universal Time Variations’, J. Geophys. Res. 71, 785–801.
Fenton, A. G., McCracken, K. G., Else, D. C., and Wilson, B. G.: 1959, ‘The Onser Times of Forbush-Type Cosmic Ray Intensity Decreases’, Can. J. Phys. 37, 970.
Goedeke, A. D. and Masley, A. J.: 1968, The 23 and 28 May 1967 Solar Cosmic Ray Events’, Symposium on Solar Flares and Space Research, Tokyo, North Holland, Amsterdam, p. 284.
Harang, L.: 1968, ‘Emission of VLF During the Great Disturbance of 25/26 May 1967’, Planetary Space Sci. 16, 1081–1094.
Lindgren, S. T.: 1968, ‘The Solar Particle Events of May 23 and May 28, 1967’, Solar Phys. 5, 382.
Mathews, T., Mercer, J. B., and Venkatesan, D.: 1968, ‘Anisotropy in Cosmic Ray Intensity Associated with Forbush Decreases’, Can. J. Phys. 46, 854–858.
McCracken, K. G., Fowler, B. C., Shea, M. A., and Smart, D. F.: 1965, ‘Cosmic Ray Tables, Asymptotic Directions, Variational Coefficients and Cut-Off Rigidities’, IQSY, Instruction Manual No. 10. (also 1968, IQSY Annals 1, 198).
Meng, C.-I. and Akasofu, S.-I.: 1967, ‘The Geomagnetic Storm of April 17–18, 1965’, J. Geophys. Res. 72, 4905–4916.
Mercer, J. B., and Wilson, B. G.: 1968, ‘Morphology of the March 23, 1966, Forbush Decrease’, Can. J. Phys. 46, 849–853.
Nagashima, K., Duggal, S. P., and Pomerantz, M. A.: 1968, ‘Cosmic Ray Anisotropy in ThreeDimensional Space’, Planetary Space Sci. 16, 29–46.
Nishida, A.: 1968, ‘Geomagnetic DP2 Fluctuations and Associated Magnetospheric Phenomena’, J. Geophys. Res. 73, 1795–1804.
Reid, G. C. and Sauer, H. H.: 1967, ‘Evidence for Nonuniformity of Solar-Proton Precipitation over the Polar Caps’, J. Geophys. Res. 72, 4383–4390.
Smith, R. W. and Webber, N. J.: 1968, ‘The Geomagnetic Storm and Aurora of 25–26 May 1967’, J. Atmospheric Terrest. Phys. 30, 169–174.
Sugiura, M. and Chapman, S.: 1960, ‘The Average Morphology of Geomagnetic Storms with Sudden Commencement’, Akad. Wiss. Göttingen.
Van Allen, J. A.: 1968, ‘Solar X-Ray Flares on May 23, 1967’, Astrophys. J. 152, 185.
Wada, M.: 1967, ‘A Storm-Time Increase in Cosmic-Ray Intensity on May 25–26, 1967’, Rep. Ionosphere Space Res. Japan 21, 223–228.
Yoshida, S. and Akasofu, S.-I.: 1966, ‘The Development of the Forbush Decrease and the Geomagnetic Fields’, Planetary Space Sci. 14, 979–986.
Yoshida, S., Akasofu, S.-I., and Kendall, P. C.: 1968, ‘Ring Current Effects on Cosmic Rays’, J. Geophys. Res. 73, 3377–3394.
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Akasofu, S.I., Perreault, P.D. & Yoshida, S. The geomagnetic and cosmic-ray storm of May 25/26, 1967. Sol Phys 8, 464–476 (1969). https://doi.org/10.1007/BF00155393
Received:
Issue Date:
DOI: https://doi.org/10.1007/BF00155393