DOI: 10.5061/dryad.rjdfn2zqb
title: Data from: A galactic cosmic ray cavity in Earth-Moon space

description: This dataset contains galactic cosmic ray (GCR) proton measurements on the
 lunar surface collected by the Chang’E-4/LND instrument, together with
 interplanetary magnetic field (IMF) and solar wind parameters from the
 ARTEMIS mission. The LND data span 31 lunar cycles from January 2019 to
 January 2022 and are provided at a one-minute cadence, while the ARTEMIS
 data have been resampled to match this temporal resolution. The dataset
 also includes test particle simulation outputs of energetic protons at 20
 MeV and 100 MeV in the near-lunar environment, including ensemble-averaged
 density maps and orbital-phase-dependent statistics used to generate
 Figures 5A–D. In addition, lists of start and end times of
 stream/corotating interaction regions (S/CIRs) and interplanetary coronal
 mass ejections (ICMEs) are provided to exclude periods affected by
 transient solar wind disturbances.
description: # Data from: A galactic cosmic ray cavity in Earth-Moon space Dataset DOI:
 [10.5061/dryad.rjdfn2zqb](https://doi.org/10.5061/dryad.rjdfn2zqb) ##
 Description of the data and file structure This dataset contains galactic
 cosmic ray (GCR) proton measurements on the lunar surface obtained by the
 Chang’E 4/LND experiment, together with interplanetary magnetic field
 (IMF) and solar wind parameters measured by the ARTEMIS mission. The
 ARTEMIS data have been resampled to a one-minute cadence to match the
 temporal resolution of the LND observations. The uploaded LND data files
 (`01.txt`–`38.txt`) cover 31 lunar cycles from January 2019 to January
 2022 and are used for the analyses presented in Figures 3–4 of the
 associated manuscript. Figures 1 and 2 rely on the uploaded Chang’E 4/LND
 dataset and publicly available ARTEMIS measurements and thus do not
 require additional figure-specific data files. In addition, lists of the
 start and end times of stream/corotating interaction region (S/CIR) and
 interplanetary coronal mass ejection (ICME) events are provided and are
 used to exclude periods affected by transient solar wind disturbances. The
 dataset also includes simulation outputs and derived products used to
 generate Figure 5 (A–D). These data are obtained from test-particle
 simulations of energetic protons propagating in the near-lunar environment
 at energies of 20 MeV and 100 MeV. For each energy, multiple independent
 realizations are performed on a fixed two-dimensional spatial grid
 extending from −100 to +100 R~E~ in both x and y directions.
 Ensemble-averaged, normalized particle density maps are provided for
 Figures 5A and 5C, and orbital phase–dependent mean particle densities
 with corresponding standard errors are provided for Figures 5B and 5D. ###
 Files and variables #### Files: 01.txt - 38.txt **Description:** This file
 contains proton flux, proton count rate, interplanetary magnetic field
 (IMF), solar wind parameters, and lunar geometry information for the lunar
 day after the Chang’E-4 landing (as indicated in the file name, i.e. 01 is
 first day, 02 is second day, etc.), measured by Chang’E 4/LND and the
 ARTEMIS mission. The data are provided at a 1-minute time resolution and
 are used for the statistical analyses in Figures 3–4 of the associated
 manuscript. Each row corresponds to one time step. The file contains **28
 columns**, ordered as follows: 1. Time (UT) 2. Proton flux (9.18–34.14
 MeV) 3. Proton flux (9.18–21.20 MeV) 4. Proton flux (21.20–34.14 MeV) 5.
 Proton flux (34.94–41.76 MeV) 6. Proton flux (42.3–139.2 MeV) 7. Proton
 flux (139.2–368.4 MeV) 8. Proton count rate (9.18–34.14 MeV) 9. Proton
 count rate (9.18–21.20 MeV) 10. Proton count rate (21.20–34.14 MeV) 11.
 Proton count rate (34.94–41.76 MeV) 12. Proton count rate (42.3–139.2 MeV)
 13. Proton count rate (139.2–368.4 MeV) 14. IMF Bx (nT) 15. IMF By (nT)
 16. IMF Bz (nT) 17. IMF total magnetic field strength |B| (nT) 18. Solar
 wind proton density (cm⁻³) 19. Solar wind velocity (km s⁻¹) 20. Bx / |B|
 21. (Bx + By) / |B| 22. Lunar phase 23. Moon position X component in GSE
 coordinates (R~E~) 24. Moon position Y component in GSE coordinates (R~E~)
 25. Moon position Z component in GSE coordinates (R~E~) 26. Angle between
 IMF and the Earth–Moon direction (degrees) 27. Angle between IMF and the
 LND field of view (degrees) 28. Lunar phase #### File: SA_FIG3.m
 **Description:** This file contains the MATLAB code used to process the
 data and generate Figure 3 of the associated manuscript. #### File:
 SIR.txt **Description:** This file lists the start and end times of
 stream/corotating interaction region (S/CIR) events used to identify and
 exclude time intervals affected by recurrent solar wind disturbances in
 the statistical analysis. #### File: ICME.txt **Description:** This file
 lists the start and end times of interplanetary coronal mass ejection
 (ICME) events. #### File: errorbar_xc.m **Description:** This MATLAB
 function is used by `SA_FIG3.m` and `SA_FIG4.m` to calculate binned mean
 values and their statistical uncertainties. #### File: SA_FIG4.m
 **Description:** This file contains the MATLAB code used to process the
 data and generate Figure 4 of the associated manuscript. #### File:
 process_fig5CD_data.py **Description:** This Python code processes
 test-particle simulation outputs at 100 MeV to generate ensemble-averaged,
 normalized spatial particle density distributions used for Figures 5C and
 5D of the associated manuscript. #### File: process_fig5AB_data.py
 **Description:** This Python code processes test-particle simulation
 outputs at 20 MeV to generate ensemble-averaged, normalized spatial
 particle density distributions used for Figures 5A and 5B of the
 associated manuscript. #### File: SA_FIG5CD.py **Description:** This
 Python code reads the processed simulation data and produces the
 visualization for Figures 5C and 5D, including the two-dimensional
 particle density map and the corresponding orbital-phase-dependent
 statistics at 100 MeV. #### File: SA_FIG5AB.py **Description:** This
 Python code reads the processed simulation data and produces the
 visualization for Figures 5A and 5B, including the two-dimensional
 particle density map and the corresponding orbital-phase-dependent
 statistics at 20 MeV. #### File: orbit_statistics_20MeV.txt
 **Description:** This file contains orbital-phase-dependent mean particle
 densities and their standard errors derived from the 20 MeV test particle
 simulations. These data are used to generate Figure 5B of the associated
 manuscript. #### File: orbit_statistics_100MeV.txt **Description:** This
 file contains orbital-phase-dependent mean particle densities and their
 standard errors derived from the 100 MeV test particle simulations. These
 data are used to generate Figure 5B of the associated manuscript. ####
 File: overview_dis_density_100MeV.txt **Description:** This file contains
 the ensemble-averaged and globally normalized spatial distribution of
 energetic protons at 100 MeV obtained from test particle simulations. The
 data are used to generate Figure 5C of the associated manuscript. ####
 File: overview_dis_density_20MeV.txt **Description:** This file contains
 the ensemble-averaged and globally normalized spatial distribution of
 energetic protons at 20 MeV obtained from test-particle simulations. The
 data are used to generate Figure 5C of the associated manuscript. ##
 Code/software All data processing and figure generation were performed
 using **Python 3.10 **and **MATLAB R2017a**. The Python codes rely on
 standard scientific libraries, including **NumPy**, **Matplotlib**, and
 **os**. The included scripts are organized as follows: *
 `process_fig5AB_data.py` / `process_fig5CD_data.py ` – Python codes to
 process test particle simulation outputs for Figures 5 (A–D). These
 scripts calculate ensemble-averaged particle density maps and
 orbital-phase-dependent statistics. * `SA_FIG5AB.py` / `SA_FIG5CD.py` –
 Python codes to generate Figures 5 (A–D) from the processed data. *
 `SA_FIG3.m` / `SA_FIG4.m` – MATLAB codes used to generate Figures 3 and 4,
 including data selection and statistical analyses. * `errorbar_xc.m` –
 MATLAB function called by `SA_FIG3.m` and `SA_FIG4.m` to compute local
 means and standard errors for plotting. **Workflow:** 1. For Figures 3–4,
 the LND observational data files (`01.txt–38.txt`) are processed in MATLAB
 using `SA_FIG3.m` / `SA_FIG4.m`, with errorbar_xc.m used for statistical
 calculations. 2. For Figure 5 (A–D), the Python codes process simulation
 outputs to produce normalized particle density maps and orbital-phase
 statistics. The `SA_FIG5AB.py` / ` SA_FIG5CD.py` scripts generate the
 final figures. No additional proprietary software is required to view or
 use the processed data files, which are provided in plain text format. ##
 Access information Other publicly accessible locations of the data: * The
 IMFand solar wind parameters used in this study are publicly available
 from the ARTEMIS mission archive at
 [http://themis.ssl.berkeley.edu/data/themis/](http://themis.ssl.berkeley.edu/data/themis/) Data was derived from the following sources: * Chang’E 4/ LND experiment measurements of galactic cosmic ray (GCR) proton count rates on the lunar far-side surface (2019–2022). * ARTEMIS mission measurements of IMF and solar wind parameters.