Logo
ScienceStack
Table of Contents
Fetching ...
Sign In

Diverse properties of electron Forbush decreases revealed by the Dark Matter Particle Explorer

F. Alemanno, Q. An, P. Azzarello, F. C. T. Barbato, P. Bernardini, X. J. Bi, H. Boutin, I. Cagnoli, M. S. Cai, E. Casilli, J. Chang, D. Y. Chen, J. L. Chen, Z. F. Chen, Z. X. Chen, P. Coppin, M. Y. Cui, T. S. Cui, I. De Mitri, F. de Palma, A. Di Giovanni, T. K. Dong, Z. X. Dong, G. Donvito, J. L. Duan, K. K. Duan, R. R. Fan, Y. Z. Fan, F. Fang, K. Fang, C. Q. Feng, L. Feng, S. Fogliacco, J. M. Frieden, P. Fusco, M. Gao, F. Gargano, E. Ghose, K. Gong, Y. Z. Gong, D. Y. Guo, J. H. Guo, S. X. Han, Y. M. Hu, G. S. Huang, X. Y. Huang, Y. Y. Huang, M. Ionica, L. Y. Jiang, W. Jiang, Y. Z. Jiang, J. Kong, A. Kotenko, D. Kyratzis, S. J. Lei, B. Li, M. B. Li, W. H. Li, W. L. Li, X. Li, X. Q. Li, Y. M. Liang, C. M. Liu, H. Liu, J. Liu, S. B. Liu, Y. Liu, F. Loparco, M. Ma, P. X. Ma, T. Ma, X. Y. Ma, G. Marsella, M. N. Mazziotta, D. Mo, Y. Nie, X. Y. Niu, A. Parenti, W. X. Peng, X. Y. Peng, C. Perrina, E. Putti-Garcia, R. Qiao, J. N. Rao, Y. Rong, R. Sarkar, P. Savina, A. Serpolla, Z. Shangguan, W. H. Shen, Z. Q. Shen, Z. T. Shen, L. Silveri, J. X. Song, M. Stolpovskiy, H. Su, M. Su, H. R. Sun, Z. Y. Sun, A. Surdo, X. J. Teng, A. Tykhonov, G. F. Wang, J. Z. Wang, L. G. Wang, S. Wang, X. L. Wang, Y. F. Wang, D. M. Wei, J. J. Wei, Y. F. Wei, D. Wu, J. Wu, S. S. Wu, X. Wu, Z. Q. Xia, Z. Xiong, E. H. Xu, H. T. Xu, J. Xu, Z. H. Xu, Z. L. Xu, Z. Z. Xu, G. F. Xue, M. Y. Yan, H. B. Yang, P. Yang, Y. Q. Yang, H. J. Yao, Y. H. Yu, Q. Yuan, C. Yue, J. J. Zang, S. X. Zhang, W. Z. Zhang, Yan Zhang, Yi Zhang, Y. J. Zhang, Y. L. Zhang, Y. P. Zhang, Y. Q. Zhang, Z. Zhang, Z. Y. Zhang, C. Zhao, H. Y. Zhao, X. F. Zhao, C. Y. Zhou, X. Zhu, Y. Zhu, X. Luo

TL;DR

This study analyzes eight CRE Forbush decreases observed by DAMPE in the $2$–$20$ GeV range from 2016 to 2024, revealing that recovery times exhibit diverse energy dependencies across events. By combining DAMPE measurements with CME parameters from the WSA-Enlil model and a diffusion-barrier transport framework, the authors show that CME velocity, angular extent, and ejection direction jointly shape the energy dependence of FD recoveries, with an anti-correlation between the slope of the recovery-time energy dependence and $V_{ m CME}\cdot\Omega$ for most CME classes. They implement Parker’s transport equation using a stochastic differential equation approach, calibrate diffusion coefficients to AMS-02 electron data, and simulate a diffusion barrier to reproduce DAMPE time profiles. The work provides a physical interpretation of CRE FDs, linking observed recovery behaviors to heliospheric transport and CME geometry, and highlights the potential of future DAMPE-like measurements to test CME-driven diffusion models during active solar cycles.

Abstract

The Forbush decrease (FD) of cosmic rays is an important probe of the interplanetary environment disturbed by solar activities. In this work, we study the properties of 8 FDs electrons (including positrons) between 2 GeV and 20 GeV from January, 2016 to March, 2024, with the Dark Matter Particle Explorer. The maximum decrease amplitudes of these events are about 30% - 15%, and the amplitudes reduce with energy. The recovery time of these events shows diverse behaviors of their energy-dependence. Some of them show strong energy-dependence, while some have a nearly constant recovery time. It has been shown that such diverse behaviors could be related with the geometry of the disturbed regions of the interplanetary space by coronal mass ejections (CME), represented by the combined effect of the CME velocity, angular spread, and ejection direction.

Diverse properties of electron Forbush decreases revealed by the Dark Matter Particle Explorer

TL;DR

This study analyzes eight CRE Forbush decreases observed by DAMPE in the – GeV range from 2016 to 2024, revealing that recovery times exhibit diverse energy dependencies across events. By combining DAMPE measurements with CME parameters from the WSA-Enlil model and a diffusion-barrier transport framework, the authors show that CME velocity, angular extent, and ejection direction jointly shape the energy dependence of FD recoveries, with an anti-correlation between the slope of the recovery-time energy dependence and for most CME classes. They implement Parker’s transport equation using a stochastic differential equation approach, calibrate diffusion coefficients to AMS-02 electron data, and simulate a diffusion barrier to reproduce DAMPE time profiles. The work provides a physical interpretation of CRE FDs, linking observed recovery behaviors to heliospheric transport and CME geometry, and highlights the potential of future DAMPE-like measurements to test CME-driven diffusion models during active solar cycles.

Abstract

The Forbush decrease (FD) of cosmic rays is an important probe of the interplanetary environment disturbed by solar activities. In this work, we study the properties of 8 FDs electrons (including positrons) between 2 GeV and 20 GeV from January, 2016 to March, 2024, with the Dark Matter Particle Explorer. The maximum decrease amplitudes of these events are about 30% - 15%, and the amplitudes reduce with energy. The recovery time of these events shows diverse behaviors of their energy-dependence. Some of them show strong energy-dependence, while some have a nearly constant recovery time. It has been shown that such diverse behaviors could be related with the geometry of the disturbed regions of the interplanetary space by coronal mass ejections (CME), represented by the combined effect of the CME velocity, angular spread, and ejection direction.
Paper Structure (6 sections, 10 equations, 11 figures, 1 table)

This paper contains 6 sections, 10 equations, 11 figures, 1 table.

Table of Contents

  1. Properties of 8 CRE FDs and the associated CMEs
  2. Pre-selection efficiency
  3. Background subtraction
  4. Exposure correction at low energies
  5. Electron transport in the heliosphere
  6. The diffusion barrier model of FD

Figures (11)

  • Figure 1: Time profiles of CRE fluxes in four energy bins measured by DAMPE in November, 2021 (blue dots), compared with the DAMPE $T_0$ rate (green curves) and OULU NM data (red curves). The errorbars of the DAMPE CRE fluxes include both the statistical uncertainties and systematic uncertainties, added in quadrature. The 4 panels correspond to 4 different CRE energy bins as labelled. Arrows in the top-left panel show the two step decreases revealed by the NM data and DAMPE $T_0$ data, and the black dashed line shows the arrival time of the interplanetary shock.
  • Figure 2: The decrease amplitude as a function of energy, for the eight FDs observed by DAMPE.
  • Figure 3: The recover time as a function of energy, for the eight FD observed by DAMPE. The solid line in each panel shows the best-fit power-law result.
  • Figure 4: Possible relationship between $b$ and $V_{\rm CME}\cdot\Omega$ as revealed by the DAMPE detected FDs. The dashed lines divide the CMEs schematically into head-on events (I), glacing events (III), and intermediate ones (II).
  • Figure S1: The CRE pre-selection effciency as a function of reconstructed energy.
  • ...and 6 more figures