;+ ; PROJECT: CHIANTI ; ; CHIANTI is an Atomic Database Package for Spectroscopic Diagnostics ; of Astrophysical Plasmas. It is a collaborative project involving ; the Naval Research Laboratory (USA), the University of Florence ; (Italy), the University of Cambridge and the Rutherford Appleton ; Laboratory (UK). ; ; NAME: ; ; FB_RAD_LOSS ; ; PURPOSE: ; ; Calculate the total radiative losses of a plasma due to the ; free-bound (radiative recombination) continuum. ; ; EXPLANATION ; ; This routine does not use the same method of calculating the ion ; continuum emissivities as the FREEBOUND routine. This is because a ; modified version of FREEBOUND would be very slow for this purpose. ; Instead, we use the method of Mewe et al. (A&AS 65, 511, 1986) which ; is outlined in their Sect.2.2. The integration over the quantity ; P_c(lambda,T) is very simple as the gaunt factor, G_c, has no ; intrinsic lambda dependence other than through the limits. ; ; Comparisons between the wavelength-resolved continuum emission ; derived from the Mewe et al. method with the more sophisticated ; method employed in FREEBOUND show excellent agreement with at most ; 10% differences at specific wavelengths. ; ; CALLING SEQUENCE: ; ; fb_rad_loss, temp, int, min_abund=min_abund, /no_setup ; ; OUTPUTS ; ; TEMP Temperatures (K). These are the temperatures at which the ; ion fractions are defined (typically 10^4 to 10^8 in 0.1 ; dex intervals). ; ; INT The emissivity in units of erg cm^3 s^-1. ; ; ; OPTIONAL INPUTS: ; ; MIN_ABUND Exclude elements whose abundances are less than MIN_ABUND. ; (Note that Ab(H)=1.) ; Abund_File: Specifies the element abundance file to be ; used. ; Ioneq_File: Specifies the ionization equilibrium file. ; Element: If set, then only the specified element will be ; included in the calculation. Can be either an ; integer (e.g., 26 for iron), or a string (e.g., 'fe' ; for iron). ; Sngl_Ion: Specifies individual ions to be included in the ; calculation. The names are given in CHIANTI format ; (e.g., 'o_6'). Can be an array of ion names. Note ; that the ion specifies the recombining ion. ; ; KEYWORD PARAMETERS: ; ; NO_SETUP If the procedure setup_elements has already been called ; then the keyword /nosetup should be set to avoid ; repeating this step ; ; PROGRAMMING NOTES ; ; This routine computes the free-bound gaunt factor following the ; prescription set out in Sect.2.2 of Mewe et al. (1986). The ; expression for f_2 (Eq. 16 of Mewe et al.) contains several ; quantities that need to be computed. Zeta_0 is computed internally ; by the function ZETA_0 through a prescription evident from browsing ; Table I of Mewe et al. Z_0 is computed from the ionization potential ; of the recombined ion which is contained in the .ip file within the ; database. The quantity n_0 (also used in deriving Z_0) is derived ; using the routine CONF2N which extracts the highest n value from ; the configuration description of the ground term of each ion. ; ; The quantity Z is just the charge on the recombined ion; E_0 is the ; ionization potential of the recombined ion, while E_n_0+1 is derived ; from Mewe's Eq.7 with the prescription that z_n=Z and n=n_0+1. ; ; The ions that are considered for the continuum are those for which ; .fblvl files exist. ; ; INTERNAL FUNCTIONS ; ; ZETA_0 ; ; CALLS ; ; READ_IP, ZION2FILENAME, SETUP_ELEMENTS, FILE_EXIST, ; READ_FBLVL, CONCAT_DIR, GET_IEQ ; ; EXAMPLES ; ; IDL> fb_rad_loss,temp,int ; IDL> plot,temp,int,/xlog,/ylog ; IDL> fb_rad_loss,temp,int,element='fe' ; IDL> fb_rad_loss,temp,int,sngl_ion=['o_7','o_8'] ; ; MODIFICATION HISTORY: ; ; Ver.1, 1-Aug-2002, Peter Young ; Completely new version of fb_rad_loss. Incorporates code from ; a version of freebound not available in CHIANTI. ; ; V 2, 25-May-2005, GDZ ; corrected routine header. ; ; Ver.3, 8-Aug-2017, Peter Young ; added abund_file and ioneq_file optional inputs. ; ; Ver.4, 30-Apr-2019, Peter Young ; added ELEMENT and SNGL_ION optional inputs; removed common ; block. ; ; VERSION: 4, 30-Apr-2019 ; ;- FUNCTION zeta_0, iz, ion ;+ ; NAME ; ; ZETA_0 ; ; EXPLANATION ; ; Returns the value of zeta_0 (the number of vacancies in the ion given ; by IZ and ION). See Sect. 2.2 of Mewe et al. (1986, A&AS 65, 511). ; ; INPUTS ; ; IZ Atomic number of ion (e.g., 26 -> Fe) ; ; ION Spectroscopic number of ion (e.g., 13 -> XIII) ; ; OUTPUTS ; ; Value of zeta_0. ;- CASE 1 OF (iz-ion) GT 22: return,double(ion-iz+55) ((iz-ion) LE 22) AND ((iz-ion) GT 8): return,double(ion-iz+27) ((iz-ion) LE 8) AND ((iz-ion) GT 0): return,double(ion-iz+9) (iz-ion) LE 0: return,double(ion-iz+1) ENDCASE END PRO fb_rad_loss, temp, int, min_abund=min_abund, $ no_setup=no_setup, abund_file=abund_file, ioneq_file=ioneq_file, $ element=element, sngl_ion=sngl_ion IF n_params() LT 2 THEN BEGIN print,'Use: IDL> fb_rad_loss, temp, int [, /no_setup, min_abund=, abund_file=' print,' ioneq_file=, sngl_ion=, element= ]' return ENDIF z_lbl=['h','he','li','be','b','c','n','o','f','ne','na','mg','al','si',$ 'p','s','cl','ar','k','ca','sc','ti','v','cr','mn','fe','co','ni',$ 'cu','zn'] ; ; Read element abundances ; IF n_elements(abund_file) EQ 0 THEN BEGIN abund_file=ch_choose_abund() ENDIF read_abund,abund_file,abund,abund_ref ; ; Apply min_abund (if set). ; IF n_elements(min_abund) NE 0 THEN BEGIN k=where(abund LE min_abund,nk) IF nk NE 0 THEN abund[k]=0. ENDIF ELSE BEGIN min_abund=0. ENDELSE ; ; Handle the input 'element'. ; elt_iz=-1 IF n_elements(element) NE 0 THEN BEGIN IF datatype(element) EQ 'STR' THEN BEGIN z2element,indgen(30)+1,elt,/symbol,/lower_CASE k=where(strlowcase(element) EQ elt,nk) IF nk NE 0 THEN elt_iz=k[0]+1 ENDIF ELSE BEGIN elt_iz=element[0] ENDELSE ab_save=abund abund=abund*0. abund[elt_iz-1]=ab_save[elt_iz-1] ENDIF IF n_elements(ioneq_file) EQ 0 THEN ioneq_file=!ioneq_file read_ioneq,ioneq_file,ioneq_t,ioneq,ioneq_ref t=10.^ioneq_t n_ioneq_t=n_elements(ioneq_t) IF n_elements(sngl_ion) NE 0 THEN BEGIN n=n_elements(sngl_ion) ioneq_save=ioneq ioneq=ioneq*0. FOR i=0,n-1 DO BEGIN convertname,sngl_ion[i],iz,ion ioneq[*,iz-1,ion-1]=ioneq_save[*,iz-1,ion-1] ENDFOR ioneq_save=0. ENDIF read_ip,concat_dir(concat_dir(!xuvtop, 'ip'), 'chianti.ip'),ionpot,ipref temp=double(10.^ioneq_t) nt=n_elements(temp) g_fb=dblarr(nt) int=dblarr(nt) temp6=temp/1d6 ehcm=ionpot[0,0] ; H ionization potential IF n_elements(min_abund) EQ 0 THEN min_abund=0. FOR iz=1,30 DO BEGIN IF abund[iz-1] GT min_abund THEN BEGIN FOR ion=1,iz DO BEGIN ieq=get_ieq(temp,iz,ion+1,ioneq_logt=ioneq_t,ioneq_frac=ioneq) IF total(ieq) NE 0. THEN BEGIN ; ; need to read in .elvlc file to get n for ground state of recombined ion ; zion2filename,iz,ion,name name=name+'.fblvl' IF file_exist(name) EQ 0 THEN GOTO,lbl1 read_fblvl,name,l1,conf,pqn,ll,spd,mult,ecm,ecmth,ref ; ; compute gaunt factor ; n_0=pqn[0] z_0=sqrt(ionpot[iz-1,ion-1]/ehcm)*n_0 e_0=ionpot[iz-1,ion-1]/8065.54d0/1d3 ; convert to keV e_n1=ehcm*(ion)^2/(n_0+1)^2/8065.54d0/1d3 l_0=1d8/(ionpot[iz-1,ion-1]-ecm[0]) l_n1=1d8/ehcm/(ion)^2*(n_0+1)^2 zeta0=zeta_0(iz,ion+1) ind_t=where(ieq NE 0.) IF ind_t[0] NE -1 THEN BEGIN f2=dblarr(nt) f2[ind_t]=0.9d0*zeta0*z_0^4/n_0^5*exp(0.1578*z_0^2/n_0^2/temp6[ind_t]) g_fb=(0.1578/temp6*abund[iz-1]*ieq*f2) int=int+2.051d-22*temp6/143.9*g_fb/sqrt(temp6)*exp(-143.9/l_0/temp6) f2[ind_t]=0.42d0*n_0^(-1.5)*double(ion)^4* $ exp(0.1578*double(ion)^2/(n_0+1)^2/temp6[ind_t]) g_fb=(0.1578/temp6*abund[iz-1]*ieq*f2) int=int+2.051d-22*temp6/143.9*g_fb/sqrt(temp6)*exp(-143.9/l_n1/temp6) ENDIF lbl1: ENDIF ENDFOR ENDIF ENDFOR END