10.1  The emission measure loci approach

Obtain the G(T) functions from the CHIANTI software, e.g.

gofnt, 'o_5', 580, 635, t_o_5, g_o_5,  d_o_5, $
press=1e15, abund_name=!xuvtop+'/abundance/sun_coronal.abund', $
ioneq_name=!xuvtop+'/ioneq/mazzotta_etal.ioneq'

; [default units are erg cm^+3 s^-1 sr-1 ]
; Suppose you have an O V 630 A intensity of 1812 [erg cm^-23 s^-1 sr-1]:

F_o_5= 1812./g_o_5 

plot, alog10(t_o_5), alog10(F_o_5),$
 xr=[4.5, 7.], yr=[25, 28], /yst, /xst, $
 xtit='Log T [K]',  ytit='Log F(T) [cm-5]', chars=1.3