SXT Irradiance Study with the latest response funcetions
updated with Chianti DB ver. 10

1. Brief history of the Yohkoh soft X-ray irradiance study.

1. Initial study : Loren's 1999 paper, i.e., (Acton, Weston, and Bruner, JGR, 1999, vol.104, p.14827).
2. SXT irradiance was used to study the relation between X-ray luminocity(Lx) and total magnetic flux(B), in Pevtsov et al.(2003) ApJ, vol.598, p.1387-1391.
3. Loren had some collaboration work with other scientists (i.e., with J. Lean, using ssc7/sst7 and with J. Fox with ssc16 or later).
4. My commitment started in Apr., 2008, as preparation of the poster presentation at the CAWSES meeting ("Solar Variability, Earth's Climate and the Space Environment"), held in Bozeman in June 2008. After a few months of intermission, I have revisited this theme since March, 2009.
5. We frequently use the X-ray (1-8A) flux from GOES/XRS as a reference. Due to the need to use GOES data more efficiently, I regenerated the YDB/GOES week files for 1991-2001 using the NGDC/GOES data, in order to improve the data coverage (i.e., the former week files had lots of data gaps). The updated GOES weekly files were submitted to Sam Freeland in Jun., 2008, and now it's a part of official YDB.
6. In 2018, Loren recalibrated SXT response functions by newly considering the contaminant accumulation on the pre-filter and the improved treatment of the stray light contamination (Acton, 2018, Sol. Phys., vol 293, pp.137). In response to this improvement, SXT irradiance was recalculated using the most recent Chianti atomic DB ver. 8.0. This work was performed with Nicole Albanese(Tufts Univ.) as a REU project of summer 2018 (Takeda et al., 2019, ApJ, vol 887, pp.225.).
7. In 2022, Hinode/XRT irradiance was finalized by properly considering the stray light contamination and the contamination layers developed on CCD and also XRT analysis filters. Using this result, the Lx(XRT irradiance) vs B (total unsigned magnetic flux) relation initially studided by Pevtsov et al.(2003) was revisited. In order to compare with the old results, Yohkoh/SXT irradiance was also revisited.

2. Goal of this study.

• the latest SXT response functions (Acton, 2018)
• the most recent atomic data (Chianti DB ver.10.0) assuming coronal abundance (Feldman, 1992).
• multiple wavelength range : 2.8-36.6A, 3-30A, 5-60A, 1-10A.
• multiple FOV radius : 0.5, 0.7, 0.9, 1.1, 1.2 Rs.

3. Method

• preparation of new SXT response functions based on Chianti ver.10 (cf. review of XRT response functions )
  • calculation of isothermal coronal spectrum

    /disk/yla/software/yla_ssw/recal_resp/
    --- for SXT response ---
    logTe: 5.50-8.00 by 0.05, wavelength: 0.05--500.0A by 0.05A
    solspec_ch1000_corona_chianti.genx
    solspec_ch1000_hybrid_chianti.genx
    solspec_ch1000_photos_chianti.genx
    
    --- for irradiance calculation (doesn't matter, SXT or XRT) ---
    logTe: 5.50-8.00 by 0.0025, wavelength: 0.05--210.0A by 0.05A
    solspec_ch1000_corona_chianti_xrtirrad.genx
    solspec_ch1000_hybrid_chianti_xrtirrad.genx
    solspec_ch1000_photos_chianti_xrtirrad.genx
    

  • modify SXT response generation procedure

    ~takeda/idlpro/y_legacy/sxt_resp/calc_sref.pro
    

  • modify TEEM procedure

    ~takeda/idlpro/y_legacy/sxt_resp/sxt_teem2new.pro
    IDL> calc_sref, ii_al, sre_str,/corona
    IDL> sxt_teem2new, 2,dsig_al,3,dsig_am,te,em, d_te,d_em, sre_str=sre_str
    

• re-perform the steps for the previous irradiance study
  1. initial data: 256x256 intensity images with masking outside 1.2Rs

     /disk/data/albanese/s2_2radii/maskedal1991_2radii.genx
     /disk/data/albanese/s2_2radii/maskedam1991_2radii.genx
     

  2. get disk signal from multiple sizes of FOV.

     ~takeda/idlpro/y_legacy/irrad4/get_mdisksig.pro
     output file: /disk/yla/takeda/sxt_irrad3/disksig/mdsigarr_1991.genx
     

  3. apply TEEM.

     ~takeda/idlpro/y_legacy/irrad4/msig2teem.pro
     output file: /disk/yla/takeda/sxt_irrad3/teem/mteemarr_1991.genx
     

  4. make daily averaged Te and EM.

     ~takeda/idlpro/y_legacy/irrad4/make_daily_mteem.pro
     output file: /disk/yla/takeda/sxt_irrad3/teem/daily_mteem_1991.genx
     

  5. calculate daily irradiance from daily Te and EM for specified wavelength range (e.g., 330: 3-30A, pevtsov: 2.8-36.6A).

     ~takeda/idlpro/y_legacy/irrad4/daily_mteem2irrad_pevtsov.pro
     output file: /disk/yla/takeda/sxt_irrad3/irrad/daily_mirrad_pevtsov_2001.genx
     
     IDL> restgen,file='/disk/yla/takeda/sxt_irrad3/irrad/daily_mirrad_pevtsov_2001',/inq
     .....  Data Section .....
     ** Structure MS_099025295074, 6 tags, length=38656, data length=38652:
        DATE            STRING    Array[284]
        M_IRRAD         DOUBLE    Array[5, 284]
        WBIN            FLOAT     Array[2]
        FRAD            FLOAT     Array[5]
        M_TEARR         DOUBLE    Array[5, 284]
        M_EMARR         DOUBLE    Array[5, 284]
     -----------------------------------------------------------
     

4. Obtained data

[click image to enlarge]

SXT irradadiance 3-30A with FOV 0.5,0.9 & 1.2Rs	2.8-36.6A (same as Pevtsov et al 2003)

• Comparison of 3 periods

SXT irradadiance 3-30A, FOV: 1.1Rs vs 1.2Rs	shifted curves (0.933, 0.904, 0.927)
SXT irradadiance 3-30A, FOV: 0.9Rs vs 1.2Rs	shifted curves (0.507, 0.442, 0.468)

• Yearly comparison

SXT irradadiance 3-30A, FOV: 0.9Rs vs 1.2Rs	shifted curves (0.556, 0.495, 0.490, 0.490, 0.457, 0.437, 0.462, 0.457,0.473,0.478)
SXT irradadiance 3-30A, FOV: 0.7Rs vs 0.9Rs	shifted curves (0.638, 0.646, 0.589, 0.575, 0.562, 0.525, 0.556, 0.550, 0.617, 0.603)