Galactic cosmic-ray anisotropy and its modulation in the heliomagnetosphere, inferred from air shower observation at Mt. Norikura

Nagashima, K.; Fujimoto, K.; Sakakibara, S.; Fujii, Z.; Ueno, Hiroyuki; Morishita, I.; Murakami, Kazuaki

doi:10.1007/bf02511970

Cited by 79 publications

(78 citation statements)

References 14 publications

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“…These are rather larger than galactic anisotropy (-0.06%) beyond the heliosphere (e.g. Nagashima et al, 1989). This may suggest that some additional terms may be operative in this rigidity region as will be shown below.…”

Section: Analysis Of Data and Resultsmentioning

confidence: 86%

“…Jacklyn, 1966;Nagashima et al,1989) and indicates the existence ofthe N-S anti-symmetric diurnal term. From the present observation that the phase difference between the anti-diurnal term and the semi-diurnal term is approximately 7 hours, it is concluded that the anisotropy might be of the non-collinear type, i.e., the loss-cone type of Nagashima et al (1989).…”

Section: Analysis Of Data and Resultsmentioning

confidence: 99%

“…Jacklyn (1966) proposed a bi-directional model which refers to bi-directional diffusion into a region of weakened galactic field in the solar neighborhood. Based on the observed air-shower data (at rigidity -104 GV), Nagashima et al (1989) advocated a "loss-cone" model which refers to a deficiency of intensity in an axially symmetric cone viewing in the outward direction of the galactic magnetic field towards higher northern latitude. These bi-directional anisotropies consist of the 1st order and 2nd order spherical functions at least, which transform to a north-south (N-S) asymmetric diurnal term and a semi-diurnal term (and an average intensity term) to be observed on the Earth (Nagashima, 1971).…”

Section: Introductionmentioning

confidence: 99%

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Observation of the North-South Asymmetry of Sidereal Anisotropy of Cosmic Rays at Matsushiro Underground.

Mori

Yasue

Munakata

et al. 1995

J. geomagn. geoelec

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We present the observed results of the cosmic-ray sidereal anisotropy in the primary rigidity range 550-950 GV from the Matsushiro underground (geogr. 36.50N, 138.0'E; 220 m.w.e. depth) for the period 1984-1994. The moon telescope used is ofmulti-directional with 17 channels, which scan simultaneously over the median latitude of viewings from-60° N to -15°S on the celestial sphere. We obtain significant sidereal diurnal and semi-diurnal terms in the daily variations with several s.d., being consistent with other observations. Most notably, the north-south asymmetry in the diurnal variations is confirmed without solar modulation, in which the amplitude increases as the direction of viewings of the telescopes moves southward towards and over the equator.

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Section: Analysis Of Data and Resultsmentioning

confidence: 86%

Section: Analysis Of Data and Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Observation of the North-South Asymmetry of Sidereal Anisotropy of Cosmic Rays at Matsushiro Underground.

Mori

Yasue

Munakata

et al. 1995

J. geomagn. geoelec

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“…Downward-pointing triangles: previous southern hemisphere results (Escobar et al 1960;Farley andStorey 1954, 1957;Fenton et al 1990;Gerhardy and Clay 1983). Upward-pointing triangles: previous northern hemisphere results (Alexeenko et al 1981;Alexeenko and Navarra 1985;Citron and Stiller 1958;Cranshaw and Galbraith 1954;Daudin et al 1956;Delvaille et al 1962;Gombosi et al 1975;Kifune et al 1986;Krasilnikov 1960;Lloyd-Evans 1982;Nagashima et al 1990;Sakakibara et al 1979). Circles: results from this work.…”

Section: Array Hardware and Software Descriptionmentioning

confidence: 74%

Cosmic Ray Anisotropy Studies with a Small Air Shower Array

Smith¹,

Clay²

1997

Aust. J. Phys.

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A small cosmic ray extensive air shower (EAS) array for anisotropy studies has been built and operated in the southern hemisphere for a full year. The operation of such an array is discussed as a possible prototype for a multiarray system which would be simple and reliable to operate. Data from the array are presented to add to the sparse southern hemisphere data set below energies of about 1 PeV.

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“…• E) which succeeded in detecting S o D 1 from the direction of the 6 hr local solar time, which is produced by the C-G effect due to the Earth's rotation around the Sun relative to the interplanetary cosmic-ray gas (Compton and Getting, 1935;Nagashima et al, 1989).…”

mentioning

confidence: 99%

The existence of cosmic ray sidereal anisotropies of galactic and solar origins with energies lower than 104 GeV and their modulation caused by the presumed behavior pattern of the heliomagnetosphere and of its neighboring gaseous matter in interstellar magnetic field

et al. 2012

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It is shown that the sidereal anisotropy (S i A) of cosmic rays (CRs) with energies smaller than 10 4 GeV consists of three kinds: one (GA) is of galactic origin from the direction G (α G = 0 hr; δ G = −20• ), and the other two (tail-in TA and nose-in HA) are of solar origin from the respective directions T (α T = 6 hr; δ T ∼ −24• ) and H (α H = 18 hr; δ H > 0• ) and supposed to be produced by the acceleration of CRs on the tail and nose boundaries of the heliomagnetosphere (HMS). This conclusion was arrived at in 1995 after a long-term delay since the beginning of CR observations in the early 20-th century. This delay was mainly due to the inconsistency among observations caused by the belief that the sidereal anisotropy must be unidirectional in space. The inconsistency has been solved at least qualitatively by the discovery of GA and TA. These anisotropies, including also HA, are subject, respectively, to their proper solar modulations in the HMS characterized by a polarity reversal every 11 years of the solar polar magnetic field and solar activity dependence with an 11-year periodicity. By using these modulation patterns, the origins of the three anisotropies have been determined. TA and HA thus determined inversely produce the following kinds of evidence and problems in the HMS: (1) the structure of the HMS, (2) acceleration of CRs on the boundary of the HMS, (3) CR Lens Effect of the HMS for the sharp concentration of TA and HA, (4) the proper motion (V HMS ) of the HMS relative to neighboring stars, (5) the proper motion of interstellar gaseous matter (including the magnetic field) relative to neighboring stars, and (6) the existence of the Subordinate HMS surrounding the HMS for the explanation of the duality of the motion of the HMS and also of the absence of the Compton-Getting (C-G) effect on the HMS. The present paper not only presents a brief summary of the studies of CR sidereal anisotropy made by many researchers during the 20th century leading to the present understanding, but also presents some problems to open up a new vista of the future.

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Galactic cosmic-ray anisotropy and its modulation in the heliomagnetosphere, inferred from air shower observation at Mt. Norikura

Cited by 79 publications

References 14 publications

Observation of the North-South Asymmetry of Sidereal Anisotropy of Cosmic Rays at Matsushiro Underground.

Observation of the North-South Asymmetry of Sidereal Anisotropy of Cosmic Rays at Matsushiro Underground.

Cosmic Ray Anisotropy Studies with a Small Air Shower Array

The existence of cosmic ray sidereal anisotropies of galactic and solar origins with energies lower than 104 GeV and their modulation caused by the presumed behavior pattern of the heliomagnetosphere and of its neighboring gaseous matter in interstellar magnetic field

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