FUNCTION ch_continuum, temp, wvl, photons=photons, density=density, $ pressure=pressure, $ abund_file=abund_file, em_int=em_int, dem_int=dem_int, $ sumt=sumt, ioneq_file=ioneq_file, $ sngl_ion=sngl_ion, element=element, $ advanced_model=advanced_model, min_abund=min_abund, $ kev=kev ;+ ; NAME: ; CH_CONTINUUM ; ; PURPOSE: ; Derives the total continuum spectrum from CHIANTI. The routine is ; a wrapper to the freefree, freebound and two_photon routines. ; ; CATEGORY: ; CHIANTI; continuum. ; ; CALLING SEQUENCE: ; Result = CH_CONTINUUM( Temp, Wvl ) ; ; INPUTS: ; Temp: Temperature in K (can be an array). If the input ; DEM_INT is used then the temperatures must be spaced at ; equal intervals of ; log10(T). E.g., log T=6.0, 6.1, 6.2, 6.3, ... ; Wvl: Wavelength in angstroms (can be an array). If /keV is ; set, then WVL is assumed to contain energies in keV ; units. In both cases WVL should be monotonically ; increasing. ; ; OPTIONAL INPUTS: ; Dem_Int: This should be the same size as TEMP and contain ; differential emission measure values. Specifying ; DEM_INT places a restriction on TEMP (see above). ; Em_Int: This should be the same size as TEMP and contain ; emission measure values. The emission measure is ; N_e*N_H*h, where N_e is electron number density, N_H ; is the hydrogen number density and h the plasma column ; depth. Units are cm^-5. ; Sngl_Ion: A string or string array specifying individual ions ; for which you want the continuum. Ions should be ; specified in the CHIANTI format, for example, 'fe_13' ; for Fe XIII. The name of the *recombined* ion is ; specified. For example, if you want the hydrogen ; continuum, use 'h_1' (not 'h_2'). ; Element: An array specifying which elements are used for the ; calculation. An element can be specified either ; with an integer (e.g., 26 for iron) or a string ; (e.g., 'fe' for iron). ; Abund_File: The name of a CHIANTI format element abundance ; file. If not specified then a widget will appear ; asking you to choose a file. The CHIANTI default file ; can be specified by giving !abund_file. ; Ioneq_File: The name of a CHIANTI format ionization equilibrium ; file. If not specified then the CHIANTI default file ; (!ioneq_file) will be used. ; Density: Scalar giving density (cm^-3) for the call to ; two_photon. The default is 10^10. ; Pressure: Scalar giving pressure (K cm^-3). The value is used ; to calculate the density using the input temperature ; array, and the density is input to two_photon. ; Min_Abund: Sets a minimum abundance value such that only ; elements with abundances higher than this value will ; be included in the calculation. For example ; min_abund=1e-6 will exclude the minor elements. ; ; KEYWORD PARAMETERS: ; PHOTONS: The output spectrum is given in photon units rather ; than ergs. ; SUMT: When a set of temperatures is given to FREEBOUND, the ; default is to output INTENSITY as an array of size ; (nwvl x nT). With this keyword set, a summation over ; the temperatures is performed. ; ADVANCED_MODEL: By default, this is set to 1 and thus a new ; ionization balance is calculated using the CHIANTI ; advanced models. To switch it off, set ; advanced_model=0 and either the default ion balance ; (!ioneq_file) will be used, or the one specified by ; ioneq_file=. ; KEV: If set, then the units of WVL are assumed to be keV. ; ; OUTPUTS: ; An IDL structure with the following tags: ; .wvl Input wavelength (WVL). ; .int Continuum intensity. ; .temp Input temperature (TEMP). ; .dem_int Input DEM values (set to -1 if not set). ; .em_int Input EM values (set to -1 if not set). ; .sumt Indicates if /sumt was set. ; .pressure Value of input pressure (set to -1 if not set). ; .density Value of input density (set to 10^10 if not set and ; pressure is not set). ; .kev Set to 1 if /kev was set. ; .time_stamp String giving time at which spectrum was created. ; .int_fb The freebound component of the intensity. ; .int_ff The freefree component of the intensity. ; .int_pp The two-photon component of the intensity. ; .chianti_version Version of CHIANTI used to generate spectrum. ; ; The intensity is given in units erg/cm2/s/sr/Ang. If /photons ; was set, then the units are photon/cm2/s/sr/Ang. If /keV was set, ; then the units will be /keV rather than /Ang. ; ; The output intensity will have dimensions (NWVL, NTEMP). If ; /sumt is set, then the intensity array is summed over ; temperature to give an array of size NWVL. ; ; EXAMPLE: ; IDL> wvl=findgen(100)+1. ; IDL> temp=10.^(findgen(11)/10.+6.5) ; IDL> c=ch_continuum(wvl,temp) ; ; IDL> c=ch_continuum(wvl,temp,advanced=0,density=1e8) ; ; MODIFICATION HISTORY: ; Ver.1, 25-Nov-2025, Peter Young ;- IF n_params() LT 2 THEN BEGIN print,'Use: IDL> output=ch_continuum( temp, wvl [, /photons, pressure=, abund_file=, em_int=, ' print,' dem_int=, /sumt, ioneq_file=, sngl_ion=, element=, ' print,' advanced_model= , density=] )' return,-1 ENDIF IF n_elements(pressure) NE 0 AND n_elements(density) NE 0 THEN BEGIN message,/info,/cont,'Both PRESSURE and DENSITY have been specified. Please use only one. Returning...' return,-1. ENDIF IF n_elements(pressure) GT 1 or n_elements(density) GT 1 THEN BEGIN message,/info,/cont,'PRESSURE or DENSITY must be scalars. Returning...' return,-1. ENDIF ; ; Need to define density for call to two_photon. ; density_scalar=-1. pressure_scalar=-1. ; IF n_elements(pressure) NE 0 THEN BEGIN density=pressure/temp pressure_scalar=pressure pressure_ioneq=pressure_scalar ENDIF ELSE BEGIN ; IF n_elements(density) EQ 0 THEN density=1e10 density_scalar=density density_ioneq=density_scalar ; ENDELSE IF n_elements(abund_file) EQ 0 THEN abund_file=!abund_file IF n_elements(advanced_model) EQ 0 THEN advanced_model=1b ; IF NOT keyword_set(advanced_model) THEN BEGIN IF n_elements(ioneq_file) EQ 0 THEN ioneq_file=!ioneq_file swtch=0b ENDIF ELSE BEGIN ioneq_file=concat_dir(getenv('IDL_TMPDIR'),'chianti.ioneq') log_temp=findgen(101)/20.+4.0 ioneq_data=ch_calc_ioneq(10.^log_temp, dens=density_ioneq, press=pressure_ioneq, /adv, $ outname=ioneq_file) junk=temporary(ioneq_data) swtch=1b ENDELSE freebound,temp,wvl,int_fb,abund_file=abund_file,photons=photons, $ em_int=em_int,dem_int=dem_int,ioneq_file=ioneq_file, $ element=element, sngl_ion=sngl_ion,min_abund=min_abund, $ kev=kev freefree,temp,wvl,int_ff,abund_file=abund_file,photons=photons, $ em_int=em_int,dem_int=dem_int,ioneq_file=ioneq_file, $ element=element, sngl_ion=sngl_ion,min_abund=min_abund, $ kev=kev two_photon,temp,wvl,int_pp,edensity=density,abund_file=abund_file,photons=photons, $ em_int=em_int,dem_int=dem_int,/lookup,ioneq_file=ioneq_file, $ element=element, sngl_ion=sngl_ion,min_abund=min_abund, $ kev=kev ; ; Get current time and convert to UTC for use as time_stamp. ; jd=systime(/julian,/utc) mjd=jd-2400000.5d mjd_str={ mjd: floor(mjd), time: (mjd-floor(mjd))*8.64d7 } time_stamp=anytim2utc(/ccsds,mjd_str) int=(int_fb+int_ff+int_pp)*1d-40 IF keyword_set(sumt) THEN int=total(int,2) IF n_elements(dem_int) EQ 0 THEN dem_int=-1. IF n_elements(em_int) EQ 0 THEN em_int=-1. ; ; This forces the output temperature to be a scalar if there is only ; one temperature. ; IF n_elements(temp) EQ 1 THEN temp_output=temp[0] ELSE temp_output=temp output={wvl: wvl, $ int: int, $ temp: temp_output, $ dem_int: dem_int, $ em_int: em_int, $ sumt: keyword_set(sumt), $ density: density_scalar, $ pressure: pressure_scalar, $ kev: keyword_set(kev), $ time_stamp: time_stamp, $ abund_file: abund_file, $ ioneq_file: ioneq_file, $ int_fb: int_fb*1d-40, $ int_ff: int_ff*1d-40, $ int_pp: int_pp*1d-40, $ chianti_version: ch_get_version() } ; ; Delete the temporary ioneq file. ; IF swtch THEN file_delete,ioneq_file return,output END