arXiv subjects

Xu-Lin Dong

Publications and source records attributed to Xu-Lin Dong.

4 recordsLinked to original sources

arXiv2025

Investigating the signs of evolutionary characteristics in the energy spectrum of shock wave acceleration

Under ideal conditions, the theory of shock acceleration for cosmic rays predicts that different elements should exhibit strictly identical spectral indices when accelerated to the same rigidity (R). However, recent high-precision measurements of elemental energy spectra have definitively established the existence of variations in spectral indices across different elements. This study constrains the spectral indices of cosmic-ray elements using AMS-02 and DAMPE observations within the Spatially Dependent Propagation (SDP) model. For elements with A/Z = 2, spectral indices shows significant positive correlations with both atomic number Z and mass number A, likely due to A or Z-dependent fragmentation cross-sections. Predictions indicate that the observed spectra of Ni and Zn will align with the Fe spectrum, while their injection spectra will exhibit slightly softer spectral indices compared to Fe. Future observations from AMS-02, DAMPE and HERD are expected to verify these findings, while theoretical models are needed to systematically explain this phenomenon.

astro-ph.HE↗

arXiv2024

Unveiling the Mechanisms of Electron Energy Spectrum Evolution

The electron spectrum exhibits a complex structure and has controversially proposed origins. This work reproduce the evolution of the electron spectrum based on a spatially dependent propagation (SDP) model. The key point is that our SPD model features two diffusion regions leading to two diffusion timescales, competing with the cooling timescale. This results in a three-segment power-law electron spectrum: (1) The spectrum below tens of GeV is primarily influenced by cooling effects from distant sources. (2) The spectrum dominated by diffusion effects from nearby sources from tens of GeV to TeV. (3) The spectrum above TeV, which is predominantly governed by cooling effects from nearby sources. This evolution is unique to the SDP model, and we offer a comprehensive and clear depiction of electron evolution under a single propagation scenario for the first time.

hep-ph↗

arXiv2023

A new understanding of nuclei spectra properties with propagation model

The AMS-02 experiment has observed new properties of primary cosmic rays (CRs) categorized into two groups: He-C-O-Fe and Ne-Mg-Si-S, which are independent of CR propagation. In this study, we investigate the unexpected properties of these nuclei using a spatial propagation model. All nuclei spectra are accurately reproduced and separated into primary and secondary contributions. Our findings include: 1. Primary CR spectra are identical. 2. Our calculations align with AMS-02 results for primary-dominated nuclei within a 10\% difference, but show significant discrepancies for the secondary-dominated nuclei. 3. The primary element abundance is presented for the first time. We anticipate that the DAMPE and future HERD experiments will provide observations of nuclei spectra above TeV energy.

hep-ph↗

arXiv2023

A common origin of multi-messenger spectral anomaly of galactic cosmic rays

Recent observations of cosmic rays (CRs) have revealed a two-component anomaly in the spectra of primary and secondary particles, as well as their ratios, prompting investigation into their common origin. In this study, we incorporate the identification of slow diffusion zones around sources as a common phenomenon into our calculations, which successfully reproduces all previously described anomalies except for the positron spectrum. Crucially, our research offers a clear physical picture of the origin of CR: while high-energy ($\textrm{>200~GV}$, including the knee) particles are primarily produced by fresh accelerators and are confined to local regions, low energy ($\textrm{<200~GV}$) components come from distant sources and travel through the outer diffusive zone outside of the galactic disk. This scenario can be universally applied in the galactic disk, as evidenced by ultra-high energy diffuse $\rm\gamma$-ray emissions detected by the AS$\rm\gamma$ experiment. Furthermore, our results predict that the spectrum of diffuse $\rm\gamma$-ray is spatial-dependent, resting with local sources, which can be tested by LHAASO experiment.

astro-ph.HE↗