User Guidance for using 3D electron density products of the corona reconstructed by tomography
techniques using pB images from STEREO/COR1A (see N3D_COR1B/ for 3D density data from COR1B)
(Second release on 05/06/2025)
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  fits/  including standard fits files for 3D electron density reconstructed for Carrington Rotations 
         CR2053 to CR 2153 respective to the Earth. There are two reconstructions in each CR, 
         corresponding to the first and second half of CR. For each reconstrcution period, two
 	 solutions are calculated with the regularization parameter, mu=1 and 10 
	 (e.g, the file "n3d_CR2053P1_m1.0.fits" is the density solution, reconstructed with 
 	 mu=1.0 for the first half of CR 2053. The 3D density is reconstructed on a spheric grid
	 361x181x51 in longitude, latitude, and radial distance. For the detailed method, refer to
         the publication of Wang, T., Arge, C.N., & Jones, S., "Improved Tomographic Reconstruction 
         of 3D Global Coronal Density from STEREO/COR1 Observations", Solar Physics, (2025) 300:46 
	 doi: 10.1007/s11207-025-02454-8   

  gif/   including gif images for density distributions at 2.5 Rsun for each reconstruction solution.

  IDL-read/ providing an idl routine "rfits_n3d.pro" to read the fits file with information including
         the grid coordinates and filenames of original data used for the reconstruction. Examples 
	 for reading the fits data and showing the result are also included.

  Mov/   including mp4 movies for displaying density maps at 2.5 Rsun for solutions with mu=1 and 10
	 for COR1A, and the movies for comparison between COR1-A and -B solutions.
  
  Source-Code/ including the F90 source code package (Ne3dTomo_V1.1) for 3D density reconstructions.
	 This version of code implements the computation on spheric grid with OpenMP. The code package
         on Cartesian grid and spheric grid with single thread (Ne3dTomo_V1.1) are available in 
	 N3D_COR1B/Source-Code. In addition, this version of code package provides IDL procedures with 
	 examples to demonstrate how to prepare input data used by F90 code for density reconstructions.

  stereo-pos/ including text files giving information about spacecrafe positions of STEREO-A and -B at 
         the middle time of each reconstruction period. The file "n3d_times.list" contains the start
         and end times for each reconstruction period for Carrington Rotations relative to the Earth.