Cosmic rays and climate Ormes, Jonathan F.
Advances in space research,
11/2018, Letnik:
62, Številka:
10
Journal Article
Recenzirano
Climate change and global warming is generally attributed to increases in greenhouse gases in the atmosphere. Other possible contributing effects are constantly being sought. Because of the ...importance of solar irradiance as a driver of climate, and because the widely known effect of the solar cycle on cosmic rays, it has been speculated for more than 50years that cosmic ray variations may have an impact on climate. The question has been how. A proposed mechanism would be through the effect of ionization from cosmic rays on the rates of nucleation of cloud condensation nuclei. The result would be an impact of the rate of cosmic rays on cloud formation that would subsequently impact the reflection of incoming short wavelengths and the trapping of outgoing long radiation; more cosmic rays would lead to more clouds and a net cooling of the planet (and visa-versa). This paper concludes that while the effect may operate, it is not sufficiently robust to be a significant contributor to the current warming of the planet.
ABSTRACT The BESS-Polar Collaboration measured the energy spectra of cosmic-ray protons and helium during two long-duration balloon flights over Antarctica in 2004 December and 2007 December at ...substantially different levels of solar modulation. Proton and helium spectra probe the origin and propagation history of cosmic rays in the galaxy, and are essential to calculations of the expected spectra of cosmic-ray antiprotons, positrons, and electrons from interactions of primary cosmic-ray nuclei with the interstellar gas, and to calculations of atmospheric muons and neutrinos. We report absolute spectra at the top of the atmosphere for cosmic-ray protons in the kinetic energy range 0.2-160 GeV and helium nuclei in the range 0.15-80 GeV/nucleon. The corresponding magnetic-rigidity ranges are 0.6-160 GV for protons and 1.1-160 GV for helium. These spectra are compared to measurements from previous BESS flights and from ATIC-2, PAMELA, and AMS-02. We also report the ratio of the proton and helium fluxes from 1.1 to 160 GV and compare this to the ratios from PAMELA and AMS-02.
We calculate the -ray albedo flux from cosmic-ray (CR) interactions with the solid rock and ice in Main Belt asteroids (MBAs), Jovian and Neptunian Trojan asteroids, and Kuiper Belt objects (KBOs) ...using the Moon as a template. We show that the -ray albedo for the Main Belt, Trojans, and Kuiper Belt strongly depends on the small-body size distribution of each system. Based on an analysis of the Energetic Gamma-Ray Experiment Telescope (EGRET) data we infer that the diffuse emission from the MBAs, Trojans, and KBOs has an integrated flux of less than image cm super(-2) s super(-1) (100-500 MeV), which corresponds to image12 times the lunar albedo, and may be detectable by the forthcoming Gamma-Ray Large Area Space Telescope (GLAST). If detected by GLAST, it can provide unique direct information about the number of small bodies in each system that is difficult to assess by any other method. In addition, the KBO albedo flux can be used to probe the spectrum of CR nuclei at close-to-interstellar conditions. The orbits of MBAs, Trojans, and KBOs are distributed near the ecliptic, which passes through the Galactic center and high Galactic latitudes. Therefore, the asteroid -ray albedo has to be taken into account when analyzing weak -ray sources close to the ecliptic, especially near the Galactic center, and signals at high Galactic latitudes, such as the extragalactic -ray emission. The asteroid albedo spectrum also exhibits a 511 keV line due to secondary positrons annihilating in the rock. This may be an important and previously unrecognized celestial foreground for the International Gamma-Ray Astrophysics Laboratory (INTEGRAL) observations of the Galactic 511 keV line emission including the direction of the Galactic center.
We calculate the {gamma}-ray albedo flux from cosmic-ray (CR) interactions with the solid rock and ice in Main Belt asteroids and Kuiper Belt objects (KBOs) using the Moon as a template. We show that ...the {gamma}-ray albedo for the Main Belt and Kuiper Belt strongly depends on the small-body mass spectrum of each system and may be detectable by the forthcoming Gamma Ray Large Area Space Telescope (GLAST). The orbits of the Main Belt asteroids and KBOs are distributed near the ecliptic, which passes through the Galactic center and high Galactic latitudes. If detected, the {gamma}-ray emission by the Main Belt and Kuiper Belt has to be taken into account when analyzing weak {gamma}-ray sources close to the ecliptic, especially near the Galactic center and for signals at high Galactic latitudes, such as the extragalactic {gamma}-ray emission. Additionally, it can be used to probe the spectrum of CR nuclei at close-to-interstellar conditions, and the mass spectrum of small bodies in the Main Belt and Kuiper Belt. The asteroid albedo spectrum also exhibits a 511 keV line due to secondary positrons annihilating in the rock. This may be an important and previously unrecognized celestial foreground for the INTErnational Gamma-Ray Astrophysics Laboratory (INTEGRAL) observations of the Galactic 511 keV line emission including the direction of the Galactic center.
The program related to Astroparticle Physics studies in the Laboratory for High Energy Astrophysics at NASA's Goddard Space Flight Center are described. This paper focuses on the results from the ...Compton Gamma Ray Observatory, ROSAT, and ASCA, missions which study emissions from very hot plasmas, nuclear processes and high energy particle interactions in space. Results to be discussed include gamma ray beaming from Active Galactic Nuclei, gamma ray emission from pulsars, radioactive elements in the interstellar medium, X-ray emission from clusters of galaxies, and the progress being made to unravel the gamma ray burst mystery. Future planned missions such as the X-ray Timing Explorer and Astro-E are also discussed.
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