C+
C NAME:
C	ThomsonElectronS10
C PURPOSE:
C	Determines the intensity scattered from single coronal electron
C	by Thomson scattering in S10 units
C CALLING SEQUENCE:
	function ThomsonElectronS10(ElSun,SinChi,U,APM, P)
C INPUTS:
C	ElSun	real	distance Sun-Electron (solar radii)
C	SinChi	real	sine of angle Sun-Electron-Observer
C	U	real	limb darkening coefficient
C	APM	real	apparent magnitude of the Sun
C OUTPUTS:
C	ThomsonElectronS10
C		real	scattered intensity (10^-26 S10)
C	P	real	polarization
C CALLS:
C	ThomsonS10, ThomsonElectron
C PROCEDURE:
C >	An S10 unit is `the brightness of one 10th magnitude star per square
C	degree of sky'. Replace the star by an electron at the same location
C	in the sky, and at distance ScEl away from the observer. The electron
C	is radiating by Thomson scattering of sunlight.
C >	STEP 1: Calculate the intensity (erg/s/sterad) -emitted- by the electron
C		in units of the flux -incident- on the electron from the solar
C		disk (erg/s/cm^2) (i.e. call ThomsonElectron)
C >	STEP 2: Convert to S10 units with ThomsonS10
C >	10^-26 comes from the Thomson scattering cross section, Sigma
C
C >	For purposes of integration along a line of sight
C		B = Int[0,Inf]{ n(s) I(s) ds}
C	the returned value can be used directly to get the integrated intensity
C	in 10-26 S10 if the density is specified in cm^-3 and the step size in cm.
C RESTRICTIONS:
C >	To convert to intensity -incident- on the observer from the 
C	electron one needs to multiply by 1/ScEl^2. This is NOT done here.
C >	A previous version of this subroutine (THOM_WTF) returned the quantity
C	835.9088/(1-U/3)*(10^(10-APM)/2.5*1E-14)*I
C	where I is the intensity returned by ThomsonBase and the constant
C	835.9088 = (PHYS__THOMSON*1E-26)/2.*(SUN__AU*1E13)*(MATH__RPD/SUN__RAU)^2*E14
C	This result can be retrieved from this version by multiplying by
C	(SUN__AU*1E13)*1E-26
C MODIFICATION HISTORY:
C	JUL-1996, Paul Hick (UCSD/CASS; ppick@ucsd.edu)
C-
	    real	ElSun
	    real	SinChi
	    real	U
	    real	APM
	    real	P

	! Note that ThomsonS10 ~ ElSun^(-2) and ThomsonElectron ~ ElSun^2
	! so the explicit ElSun dependence cancels.

	ThomsonElectronS10 = ThomsonS10(ElSun,APM)*ThomsonElectron(ElSun,SinChi,U,P)

	return
	end