Global Core Plasma Model, D. L. Gallagher, October 17, 2007
Version 2.1

The included Global Core Plasma Model (GCPM) code version has passed internal testing.  The features
currently included are the plasmasphere, plasmapause, magnetospheric trough, polar cap, and interface 
to the IRI95 model for ionospheric densities.  GCPM is intended to provide representative
thermal plasma densities in these regions, but is not intended to represent the distribution
of thermal plasma density at any given time.

IRI95 subroutines are included, as are subroutines for coordinate transformations.  The IRI 
subroutines included with this code-set also include the ASCII data files read by IRI (ccirxx.asc, 
ursixx.asc, and ig_rz.dat).  You will have to go into the irif13.for and the iris13.for files to 
change the FORMAT statements used with the OPEN statements to access these files.  The path to 
the files is contained in the FORMAT statements.  Search for the OPEN statements and look for 
FORMAT statements that soon follow, which point to these files.  Change the file path to correctly 
direct the code to where you locate these files.

Each of the zip files in this distribution contain subroutine libraries.  The gcpm.zip file contains 
the GCPM subroutines where the file gcpm_v21.for is the one that can be called to obtain
densities as described above.  The input and output parameters are as follows:

ccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccc
c	Input parameters:
c
c	itime	integer*4	  dimensions=2
c		(1) = yeardoy, e.g. 2001093
c		(2) = miliseconds of day
c	r	real*4        dimension=1
c		geocentric radial distance in RE
c	al	real*4	  dimensions=1
c		MacIlwain L-shell parameter (Dipole coordinates)
c	amlt	real*4	  dimension=1
c		solar magnetic local time in hours
c	amlat	real*4        dimension=1
c		solar magnetic latitude in radians
c	akp		real*4  dimension=1
c		planetary Kp index
ccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccc

ccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccc
c	Output parameters:
c	outn	real*4		dimensions=4
c			(1) = total electron density in 1/cm^3
c			(2) = total hydrogen density in 1/cm^3
c			(3) = total helium density in 1/cm^3
c			(4) = total oxygen density in 1/cm^3
ccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccc

The call line for this entry-subroutine is:

	call gcpm_v21(itime,r,amlt,alatr,akp,outn)

In addition to the GCPM library, the IRI95 and xform libraries need 
to be compiled into object code or into linkable libraries that can be 
linked to when building your executable program.

NOTE: All FORTRAN code needs to be compiled with the option to retain the 
values of local subroutine variables. This is usually not a default option 
in modern compilers. Without this compile option, the code will not work
properly.

A sample main program (test_gcpm_V21.for) for testing the gcpm code and 
the ASCII output file (test_ne.txt) it should produce are 
included with this distribution. Also included is a graphic 
(gcpm_v21_fieldaligned.jpg) created from the output file and an IDL 
program (fieldaligned_view.pro, grey2.pro) to great it.

Questions can be directed to:

Dennis L. Gallagher
NASA Marshall Space Flight Center
320 Sparkman Drive
Huntsville, AL 35805
(256)961-7687 (O)
(256)961-7215 (f)
e-mail: dennis.l.gallagher@nasa.gov