 rcore=  0.14000000000000001     
 qcore=  0.45000000000000001     
 const=  0.12698727186848197     
 ref="ae.core.dens.plt"
 g(x)=exp(-0.5*(x/rcore)**2)
 a(x)=qcore*const/rcore**3
 rhocore(x)=4*pi*x**2 *a(x)*g(x)
 set xrange [0.1*rcore:5.0*rcore]
 p rhocore(x),\
   ref       t 'ae core',\
   ref u 1:3 t 'ae val'
 show function
 pr 'to fit the core charge, select an area and'
 pr 'fit rhocore(x) ref via rcore, qcore'
