Unusual Cosmic-Ray Fluctuations on July 17 and 18, 1959

Carmichael, H.; Steljes, J. F.

doi:10.1103/physrevlett.3.392

Cited by 12 publications

(2 citation statements)

References 2 publications

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“…The increment was not present in the meson data from these observatories. This fact by itself has already prompted a number of investigators to speculate that the neutron enhancement was due to solar-produced radiation [Carmichael and Steljes, 1959;Bailey and Pomerantz, 1960]; however, the fact that the time changes during the event were unlike those of earlier flare effects has thrown some doubt on this interpretation. It is clear that we must investigate other characteristics of the anomalous increase to see whether they support the hypothesis of solar production.…”

Section: The Flare Effect Of July 17 1959mentioning

confidence: 99%

Comparison of solar cosmic rays injection including July 17, 1959, and May 4, 1960

McCracken¹,

Palmeira²

1960

J. Geophys. Res.

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Using neutron monitor data obtained at high latitudes, it is shown in Part 1 that cosmic‐ray particles of rigidity >1 bv were produced by the solar flare that occurred at 2115 UT on July 16, 1959. The exponent of the integral rigidity spectrum of the radiation was ≤−8.0. The temporal dependence of the flare radiation was unlike that of earlier flare effects, the intensity requiring ∼7 hours to reach its maximum value. No impact zones were observed. In Part 2, meson data obtained at the time of the flare effect starting at 1031 UT on May 4, 1960, are presented. In Part 3, by considering the above‐mentioned flare effects, and those observed previously, it is shown that the time scale of the cosmic‐ray flare effect is a highly variable quantity, varying by a factor as great as 36 from event to event. The flares responsible for the four flare effects with the shortest time scales occurred on the western solar limb; those resulting in the flare effects with the longest time scales occurred near the center of the solar disk. In Part 4 the above facts are shown to support the theoretical model proposed by Piddington.

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Section: The Flare Effect Of July 17 1959mentioning

confidence: 99%

Comparison of solar cosmic rays injection including July 17, 1959, and May 4, 1960

McCracken¹,

Palmeira²

1960

J. Geophys. Res.

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“…Descriptions and interpretations of the cosmic-ray events of July 17 and 18 have been presented: for example, those of Carmichael and Steljes [1959]; Wilson, Rose, and Pomerantz [1959]; Steljes and Carmichael [1960];and McCracken and Palmeira [1960).2…”

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confidence: 99%

The spectrum and propagation of relativistic solar flare particles during July 17–18, 1959

Ghielmetti¹

1961

J. Geophys. Res.

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In the interval July 17-18, 1959, one solar charged particle intensity increase was definitely observed before a sharp Forbush type decrease, and a second appeared likely following the decrease. These events were detected at sea level and at mountain altitudes. The first event followed the giant solar flare of July 16, and the solar particles appeared to arrive isotropically at the earth. The intensity time dependence of this event showed a slow rise-time comparable with its exponential decay. The integral rigidity spectrum for these particles was approximately (cp/ze)-9. The second event, although not uniquely determined as a solar flare event, followed some minor solar flare activity and might be explained by assuming an anisotropy (impact zones for the source in the solar direction) for several hours. The integral rigidity spectrum for this second event was (cp/ze)-4.5. This sequence of intensity increases could be explained by the diffusion of solar particles from the July 16 flare through disordered magnetic fields to reach the earth isotropically. The effect of the mechanism for the subsequent Forbush intensity decrease is to smooth the interplanetary fields so as to leave behind only weak, regular fields through which the fast moving solar particles of July 18 arrive anisotropically at the earth.

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