|
| | | | |
| | | |
| Stat |
Members: 3645
Articles: 2'500'096
Articles rated: 2609
18 April 2024 |
|
| | | | |
|
Article overview
| |
|
|
p, He, and C to Fe cosmic-ray primary fluxes in diffusion models: Source and transport signatures on fluxes and ratios | | A. Putze
; D. Maurin
; F. Donato
; | | Date: |
3 Nov 2010 | | Abstract: | The propagated fluxes of proton, helium, and heavier primary cosmic-ray
species (up to Fe) are a means to indirectly access the source spectrum of
cosmic rays. We check the compatibility of the primary fluxes with the
transport parameters derived from the B/C analysis, but also if they bring
further constraints. Proton data are well described in the simplest model
defined by a power-law source spectrum and plain diffusion. They can also be
accommodated by models with, e.g., convection and/or reacceleration. There is
no need for breaks in the source spectral indices below $sim 1$ TeV/n. Fits on
the primary fluxes alone do not provide physical constraints on the transport
parameters. If we let free the source spectrum $dQ/dE = q eta^{eta_S} {cal
R}^{-alpha}$ and fix the diffusion coefficient $K(R)= K_0eta^{eta_T} {cal
R}^{delta}$ such as to reproduce the B/C ratio, the MCMC analysis constrains
the source spectral index $alpha$ to be in the range $2.2-2.5$ for all primary
species up to Fe, regardless of the value of the diffusion slope $delta$. The
$eta_S$ low-energy shape of the source spectrum is degenerate with the
low-energy shape $eta_T$ of the diffusion coefficient: we find
$eta_S-eta_Tapprox 0$ for p and He data, but $eta_S-eta_Tapprox 1$ for C
to Fe primary species. This is consistent with the toy-model calculation in
which the shape of the p/He and C/O to Fe/O data is reproduced if
$eta_S-eta_Tapprox 0-1$ (no need for different slopes $alpha$). When
plotted as a function of the kinetic energy per nucleon, the low-energy p/He
ratio is shaped mostly by the modulation effect, whereas primary/O ratios are
mostly shaped by their destruction rate. | | Source: | arXiv, 1011.0989 | | Services: | Forum | Review | PDF | Favorites | |
|
|
No review found.
Did you like this article?
Note: answers to reviews or questions about the article must be posted in the forum section.
Authors are not allowed to review their own article. They can use the forum section.
browser claudebot
|
| |
|
|
|
|
News, job offers and information for researchers and scientists:
| |
REGISTER