نتایج جستجو برای: galactic cosmic ray

تعداد نتایج: 349069  

1999
R. E. Lingenfelter R. Ramaty

We show that the expected composition of cosmic rays accelerated from the erosion products of fast supernova grains in the hot interstellar medium (HISM) of ejecta enriched superbubbles, where the bulk ( 85%) of Galactic supernovae occur, is consistent with the currently available cosmic ray data. In particular, we show that if the cosmic ray metals come from the sputtering of fast refractory g...

2007
Jörg R. Hörandel

An overview is given on the present status of the understanding of the origin of galactic cosmic rays. Recent measurements of charged cosmic rays and photons are reviewed. Their impact on the contemporary knowledge about the sources and acceleration mechanisms of cosmic rays and their propagation through the Galaxy is discussed. Possible reasons for the knee in the energy spectrum and scenarios...

2007
Jörg R. Hörandel

An overview is given on the present status of the understanding of the origin of galactic cosmic rays. Recent measurements of charged cosmic rays and photons are reviewed. Their impact on the contemporary knowledge about the sources and acceleration mechanisms of cosmic rays and their propagation through the Galaxy is discussed. Possible reasons for the knee in the energy spectrum and scenarios...

2007
Jörg R. Hörandel

An overview is given on the present status of the understanding of the origin of galactic cosmic rays. Recent measurements of charged cosmic rays and photons are reviewed. Their impact on the contemporary knowledge about the sources and acceleration mechanisms of cosmic rays and their propagation through the Galaxy is discussed. Possible reasons for the knee in the energy spectrum and scenarios...

2009
R. MEWALDT R. E. VOGT

We report new high resolution measurements of the elemental and isotopic composition of galactic cosmic ray B, C, N, and 0 nuclei with ~ 30 to ~ 130 MeV nucleon-•. These observations place limits on the isotopic composition of the cosmic ray source and restrict possible models of cosmic ray origin and propagation. In particular, we find that N is significantly depleted in the cosmic ray source ...

1998
Henrik Svensmark

During the last solar cycle Earth’s cloud cover underwent a modulation more closely in phase with the galactic cosmic ray flux than with other solar activity parameters. Further it is found that Earth’s temperature follows more closely decade variations in galactic cosmic ray flux and solar cycle length, than other solar activity parameters. The main conclusion is that the average state of the ...

2006
Pasquale Blasi

It is believed that the observed diffuse gamma ray emission from the galactic plane is the result of interactions between cosmic rays and the interstellar gas. Such emission can be amplified if cosmic rays penetrate into dense molecular clouds. The propagation of cosmic rays inside a molecular cloud has been studied assuming an arbitrary energy and space dependent diffusion coefficient. If the ...

1999
Brian D. Fields

The galactic chemical evolution of Be and B provides unique information about the origin and history of cosmic rays. The available Pop II data demonstrate that Be and B have a Galactic source, probably in one or more kinds of spallation processes. However, the data are not unequivocal about the nature of Be and B origin, as encoded in the primary or secondary (linear or quadratic) scaling with ...

2008
Shane W. Davis Enrico Ramirez-Ruiz

We show that the luminosity of a star forming galaxy is capped by the production and subsequent expulsion of cosmic rays from its interstellar medium. By defining an Eddington luminosity in cosmic rays, we show that the star formation rate of a given galaxy is limited by its mass content and the cosmic ray mean free path. When the cosmic ray luminosity and pressure reaches a critical value as a...

2008
FRANCIS HALZEN

While supernova remnants have been identified as the most likely sources of the galactic cosmic rays, no conclusive observational evidence for this association exists. We show here that IceCube has the possibility of producing incontrovertible evidence by detecting neutrinos produced by the cosmic ray beam interacting with the hydrogen in the vicinity of the supernova shock expanding into the i...

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