;+
; FILE:   nedpb.pro
;* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
; PURPOSE
;	Electron density (Ne/cm2) per 1.0 Bsun brightness (pB)
;	in the solar corona.
;
; SYNTAX
;	necm2 = nedpb (r)
;
; INPUTS
;	r	radial distance from solar limb in Rsun units.
;
; OUTPUT
;	necm2	grams per 1.0 Bsun per cm^2 at the specified distance.
;
; HISTORY
;	Andrew L. Stanger   HAO/NCAR   17 June 2004
;* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
;-

FUNCTION nedpb, r

nelem  = 101		; # elements in pbtab array.
irad   = 0		;
dr     = 0.10		; delta r  (radial increment). */
romin  =  1.00		; r minimum. (radial offset). */
romax  = 11.00		; r maximum. */
Ne_val = 0.0		;
zero   = 0.0		;

;* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
;* # electrons per square cm per Bsun brightness in solar corona 
;* as a function of radius (1.00 -> 11.0 Rsun in increments of 0.1 Rsun.
;* Values computed from program jack (obtained from R. Munro).
;* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
;*/
epbtab = fltarr (nelem)

epbtab [  0 :  49] = [3.884e+25, 1.957e+25, 1.895e+25, 1.984e+25, 2.137e+25, $
                     2.327e+25, 2.547e+25, 2.790e+25, 3.054e+25, 3.337e+25, $
                     3.639e+25, 3.960e+25, 4.297e+25, 4.652e+25, 5.023e+25, $
                     5.412e+25, 5.817e+25, 6.238e+25, 6.676e+25, 7.130e+25, $
                     7.601e+25, 8.088e+25, 8.591e+25, 9.110e+25, 9.646e+25, $
                     1.020e+26, 1.076e+26, 1.135e+26, 1.195e+26, 1.257e+26, $
                     1.320e+26, 1.385e+26, 1.451e+26, 1.519e+26, 1.589e+26, $
                     1.660e+26, 1.733e+26, 1.807e+26, 1.883e+26, 1.961e+26, $
                     2.040e+26, 2.121e+26, 2.204e+26, 2.288e+26, 2.374e+26, $
                     2.461e+26, 2.550e+26, 2.640e+26, 2.733e+26, 2.826e+26]

epbtab [ 50 : 100] = [2.922e+26, 3.019e+26, 3.117e+26, 3.217e+26, 3.319e+26, $
                     3.422e+26, 3.527e+26, 3.634e+26, 3.742e+26, 3.852e+26, $
                     3.963e+26, 4.076e+26, 4.191e+26, 4.307e+26, 4.425e+26, $
                     4.544e+26, 4.665e+26, 4.788e+26, 4.912e+26, 5.038e+26, $
                     5.165e+26, 5.294e+26, 5.425e+26, 5.557e+26, 5.691e+26, $
                     5.826e+26, 5.964e+26, 6.102e+26, 6.242e+26, 6.384e+26, $
                     6.528e+26, 6.673e+26, 6.819e+26, 6.968e+26, 7.117e+26, $
                     7.269e+26, 7.422e+26, 7.577e+26, 7.733e+26, 7.891e+26, $
                     8.050e+26, 8.211e+26, 8.374e+26, 8.538e+26, 8.704e+26, $
                     8.872e+26, 9.041e+26, 9.212e+26, 9.384e+26, 9.558e+26, $
                     9.733e+26] 

   rtab = fltarr (nelem)
   rtab = indgen (nelem) * dr + romin

;   print, rtab

   IF (r LT romin)  THEN RETURN, zero
   IF (r GT romax)  THEN RETURN, zero

   irad = FIX ((r - romin) / dr)

;   print, 'r: ', r, ' romin: ', romin, ' irad: ', irad

   Ne_val = (epbtab [irad]			$
	  + (epbtab [irad+1] - epbtab [irad])	$
	  * double ((r - irad*dr - romin) / dr)) 

   RETURN, Ne_val
END