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  • 1
    Electronic Resource
    Electronic Resource
    [s.l.] : Nature Publishing Group
    Nature 181 (1958), S. 1155-1156 
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] In order to provide more information to assist in mapping the effective magnetic field, the University of Tasmania undertook a survey of the cosmic-ray nucleonic component between the longitude limits 140 ° E.-1480 E. and extending from 52 ° S. to 34 ° N. geographic latitude. A ...
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    [s.l.] : Nature Publishing Group
    Nature 177 (1956), S. 1173-1174 
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] The increase was observed at the three stations with counter telescopes, and also with a 23-litre shielded ionization chamber at Hobart. The telescopes at Hobart and Mawson have 1-metre square counter trays, the extreme tray separation being 1 -5 m. At each of these stations there are two ...
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Springer
    Space science reviews 11 (1970), S. 155-233 
    ISSN: 1572-9672
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract This review attempts to present an integrated view of the several types of solar cosmic ray phenomena. The relevant large and small scale properties of the interplanetary medium are first surveyed, and their use in the development of a quantitative understanding of the cosmic ray propagation processes summarised. Solar cosmic ray events, in general, are classified into two phenomenological categories: (a) prompt events, and (b) delayed events. The properties of both classes of events are summarised. The properties considered are the frequency of occurrence, dependence on parent flare position, the time profile, energy spectra, anisotropies, particle species, velocity dispersions, etc. A single model is presented to explain the various species of delayed event. Thus the halo and core events, energetic storm particle events, EDP events and proton recurrent regions are suggested to be essentially of common origin. The association of flare particle events with electromagnetic phenomena, including optical, X-ray and microwave emissions is summarised. The conditions in a sunspot group, and solar flare that are considered to be conducive to cosmic ray acceleration processes are discussed. Considerable discussion is devoted to physical processes occurring near the Sun. Near Sun particle storage, and diffusion, and secondary injection processes that are triggered by a far distant solar flare are reviewed. In order to explain the considerable differences between aspects of the prompt and delayed events, we propose selective diffusion processes that only occur at early times in a solar flare. The type IV radio emissions at metric wave-lengths are suggested to yield direct evidence for the storage processes that are necessary to explain the properties of the delayed events, and also as yielding direct evidence of secondary injection processes. We conclude by briefly summarising the ionospheric effects of the solar cosmic radiation.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Springer
    Solar physics 18 (1971), S. 100-132 
    ISSN: 1573-093X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract A study of the properties of the cosmic radiation of energy ∼- 10 MeV generated by solar flares is reported. Data from four Pioneer spacecraft in interplanetary orbits, and separated by ∼ 180° in heliocentric longitude are employed. Attention is restricted to the properties evident at times in excess of 1 day after the occurrence of the parent flare. The anisotropic character of the radiation; the gradients in heliocentric longitude; the decay time constants; and the energy spectra of the radiation are all studied in detail. It is found that the equilibrium anisotropy assumes a direction ∼- 45° E of the satellite-Sun line at very late times. It is suggested that the anisotropy at such times is parallel to E × B. This observation confirms that convection is the determining process in the escape of the solar cosmic rays from the solar system. It indicates that a positive radial gradient of solar cosmic radiation density has builtup at orbit of Earth some 4 days after a flare. This results in an effective convective velocity of approximately 1/2 the solar wind velocity. Direct measurements indicate the presence of strong gradients in heliocentric longitude even at very late times (≳ 4 days). These gradients are essentially invariant with respect to time, e-folding angles of n ∼- 30° have been observed at ∼- 10 MeV. The presence of these gradients has a major effect on the temporal variation of the cosmic ray flux during the decay phase of the flare effect. Thus, the observed decay time constant is either increased or decreased relative to the ‘convective’ value depending on the position of the observer relative to the centroid of the cosmic ray population injected by the flare. The effect of the gradient becomes more pronounced at lower energies, and may even exceed the convective removal rate. The observed decay time constant, the characteristics of the anisotropy, and the gradient in longitude are shown to be inter-related as demanded by theory. It is shown that the exponent of the cosmic ray spectrum is dependent on the location of the observer relative to the centroid of the cosmic ray population injected by the parent flare. At a given point in the frame of reference of the cosmic ray population, the spectral exponent is invariant with time.
    Type of Medium: Electronic Resource
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  • 5
    ISSN: 1573-093X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract Concurrent observations of the solar flare of March 12, 1969 by two spacecrafts separated in solar longitude by 38° show that the accessibility at 1 AU to cosmic ray particles is not a simple function of the relative solar longitude. The cosmic ray flux, degree of anisotropy, and rise time all indicate that the favored path for cosmic ray propagation in this event was some 40° to the east of the nominal Archimedes spiral line of force from the flare location. This is interpreted as evidence for either (a) extreme stochastical wandering of the lines of force of the interplanetary magnetic field, or (b) the redistribution of the cosmic rays in coronal magnetic fields prior to escape onto the nominal Archimedes spiral lines of force.
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    Springer
    Solar physics 26 (1972), S. 229-240 
    ISSN: 1573-093X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract Detailed particle observations from various Pioneer Spacecrafts located at different heliolongitudes during the complex solar flare events of March 30–April 10, 1969 have been utilised to investigate the energy dependence of azimuthal gradients of cosmic ray particles and its effect on the decay of the flare intensity. For an observer located to the east of the centroid of the population, the azimuthal corotation term and the convection term will be additive, resulting in a short decay time constant. An observer located to the west of the centroid of the population will experience a much longer decay time constant, the corotation term partially or completely compensating the loss of particles due to convection. At very low energies, the azimuthal corotation term may even be more than the convection term, thus resulting in a rise in intensity instead of decay during late in the event. Using the relationship showing the dependence of the spectral exponent of the cosmic ray flux late in a flare event on the azimuth from the centroid of the population given by McCracken et al., the energy dependence of the decay time constant and the cross-over energy at which the azimuthal gradient term equals the convection term are investigated. The experimental observations are shown to be generally consistent with the theoretical picture, confirming the importance of convection and the azimuthal gradient in determining the decay profile of flare events.
    Type of Medium: Electronic Resource
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  • 7
    ISSN: 1573-093X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract A discussion of the January 28, 1967 solar flare event is presented. High energy data from several neutron monitor stations are supplemented by low energy data from the interplanetary space probes Pioneers 6 and 7. A study of the data obtained from these three observation stations widely separated in solar azimuth has shown (1) the most probable location for the responsible flare was ≈ 60 ° beyond the western solar limb, (2) other than the large emitted particle flux, the phenomena associated with the January 28 activity are not atypical of other solar flare effects, (3) both the ≳ 0.5 GeV and ≳ 7.5 MeV fluxes observed at the earth were isotropic, indicative of particle diffusion across the interplanetary magnetic field lines, (4) the spectral exponent of the differential rigidity spectrum at high energies was - 4.8 ± 0.2, and (5) there was an indication of low energy solar injection prior to the high energy event of January 28. A technique is also described for obtaining the differential rigidity spectral index for an isotropic flux as a function of the relative enhancements of any pair of neutron monitors sufficiently separated in latitude.
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    [s.l.] : Nature Publishing Group
    Nature 181 (1958), S. 34-34 
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] New evidence can be obtained from a determination of the 'cosmic-ray meridian' or line on the Earth's surface along which the rate of change of cosmic-ray intensity is greatest. Depending on which theory proves most acceptable, this might be expected to coincide with the geomagnetic meridian, the ...
    Type of Medium: Electronic Resource
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  • 9
    Electronic Resource
    Electronic Resource
    [s.l.] : Nature Publishing Group
    Nature 215 (1967), S. 38-40 
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] Two identical X-ray detection systems were included in the payloads of two Skylark rockets flown from Woomera, Australia (lat. = 30-9 S., long. == 136-5 E.), at 0032 U.T. on April 4, 1967 (Skylark SL 426), and at 2236 U.T. on April 20, 1967 (Skylark SL 425). The X-ray experiments on both nights ...
    Type of Medium: Electronic Resource
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  • 10
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] The spectra of three X-ray objects have been measured from a balloon, and suggest that the sources are supernova remnants, and that the X-ray emission is due to magnetic ...
    Type of Medium: Electronic Resource
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