1. TRAD, Tests & Radiations ESWW11-session 5, November 18, 2014 Processing of the ACE/SIS heavy ion data in the frame of the ESA ESHIEM project Athina Varotsou and Anne Samaras Athina Varotsou and Anne Samaras Daniel Heynderickx, Pete Truscott, Fan Lei, Piers Jiggens

2. TRAD, Tests & Radiations 2 ESWW11-session 5, November 18, 2014Outline  Goal of the study  Characteristics of the ACE/SIS ion data  Processing of ACE/SIS ion data  Helium  Heavier ions  Multi-spacecraft He fluence profile comparisons for 14 SEP events  Conclusions

3. TRAD, Tests & Radiations 3 ESWW11-session 5, November 18, 2014 Goal of the study  Goal for this part of the study  Calculate solar energetic ion abundance ratios w.r.t. He to allow for solar ion model creation within the SEPEM system.  Need for clean He database and clean Z>2 ion database  110 SEP events between November 1997 and March 2013 have been analysed.  14 SEP events have been selected for providing more complete ion data coverage

4. TRAD, Tests & Radiations 4 ESWW11-session 5, November 18, 2014 Characteristics of the ACE/SIS ion data  ACE is operating at the L1 libration point since late 1997. SIS (Solar Isotope Spectrometer) allows to measure solar energetic particles even during large SEP events.  Available ion data: He, C, N, O, Ne, Na, Mg, Al, Si, S, Ar, Ca, Fe, Ni (Zmin=2 to Zmax=28)  8 energy ranges for each ion: from ~4 MeV/nuc (min E for He) to ~150 MeV/nuc (max E for Ni).  Data cover more than a solar cycle  High resolution data. Even smaller events are observed. ACE/SIS

5. TRAD, Tests & Radiations 5 ESWW11-session 5, November 18, 2014 Characteristics of the ACE/SIS ion data  Processing and on board priority system  During high rate periods lower priority is given to He and lower energy CNO.  In some cases obtained counts drop significantly during the peak phase of the SEP event.  Fluxes calculated from counts have to account for this unequal selection of events. This leads to a non-trivial relationship between the counts and the fluxes (and one that changes with energy, time, and species).  When counts drop, large variations are observed in the calculated fluxes and sometimes true flux is underestimated.

6. TRAD, Tests & Radiations 6 ESWW11-session 5, November 18, 2014 Characteristics of the ACE/SIS ion data  Processing and on board priority system He SEP Event 24/09/2001

7. TRAD, Tests & Radiations 7 ESWW11-session 5, November 18, 2014 Characteristics of the ACE/SIS ion data  Processing and on board priority system C SEP Event 24/09/2001

8. TRAD, Tests & Radiations 8 ESWW11-session 5, November 18, 2014 Processing of ACE/SIS ion data: He  In the frame of the ESHIEM project we need a clean He dataset  Processing of the ACE/SIS He data  256-sec Level 2 data were used  Most important correction: flux dropouts at peak phase of SEP events. Both automatic and manual processing.  1-hour averaging  Data gap filling

9. TRAD, Tests & Radiations 9 ESWW11-session 5, November 18, 2014 Processing of ACE/SIS ion data: He  September 30, 1998 (smaller event)

10. TRAD, Tests & Radiations 10 ESWW11-session 5, November 18, 2014 Processing of ACE/SIS ion data: He  July 14, 2000 (large event)

11. TRAD, Tests & Radiations 11 ESWW11-session 5, November 18, 2014 Processing of ACE/SIS ion data: He  October 26, 2003 (large event)

12. TRAD, Tests & Radiations 12 ESWW11-session 5, November 18, 2014 Processing of ACE/SIS ion data: ions  In the frame of the ESHIEM project we need a clean ion dataset  Processing of the Z>2 ACE/SIS ion data  256-sec Level 2 data were used  Dropouts at peak (less important than for He), spikes  1-hour averaging  Data gap filling

13. TRAD, Tests & Radiations 13 ESWW11-session 5, November 18, 2014 Processing of ACE/SIS ion data: ions  July 14, 2000 (large event) C

14. TRAD, Tests & Radiations 14 ESWW11-session 5, November 18, 2014 Processing of ACE/SIS ion data: ions  July 14, 2000 (large event) Fe

15. TRAD, Tests & Radiations 15 ESWW11-session 5, November 18, 2014 Multi-spacecraft He fluence profile comparisons for 14 SEP events  14 SEP events  22 Apr 1998, 30 Sept 1998  13 Jul 2000, 8 Nov 2000  2 Apr 2001, 24 Sept 2001, 4 Nov 2001, 26 Dec 2001  17 Apr 2002  26 Oct 2003  15 Jan 2005  5 Dec 2006  20 Jan 2012, 5 Mar 2012

16. TRAD, Tests & Radiations 16 ESWW11-session 5, November 18, 2014 Multi-spacecraft He fluence profile comparisons for 14 SEP events  4 He cleaned datasets were compared  ACE/SIS data  GOES/SEM data -> from SEPEM  IMP8/GME data -> from SEPEM  SOHO/ERNE data -> from SEPServer

17. TRAD, Tests & Radiations 17 ESWW11-session 5, November 18, 2014 Multi-spacecraft He fluence profile comparisons for 14 SEP events  22 April 1998

18. TRAD, Tests & Radiations 18 ESWW11-session 5, November 18, 2014 Multi-spacecraft He fluence profile comparisons for 14 SEP events  22 April 1998 ACE: high uncertainty GOES:background IMP8: large data gaps No SOHO/ERNE data

19. TRAD, Tests & Radiations 19 ESWW11-session 5, November 18, 2014 Multi-spacecraft He fluence profile comparisons for 14 SEP events  2 April 2001

20. TRAD, Tests & Radiations 20 ESWW11-session 5, November 18, 2014 Multi-spacecraft He fluence profile comparisons for 14 SEP events  2 April 2001 ACE: high uncertainty IMP8: some data gaps SOHO: possible saturation and data gaps

21. TRAD, Tests & Radiations 21 ESWW11-session 5, November 18, 2014 Multi-spacecraft He fluence profile comparisons for 14 SEP events  24 September 2001

22. TRAD, Tests & Radiations 22 ESWW11-session 5, November 18, 2014 Multi-spacecraft He fluence profile comparisons for 14 SEP events  2 April 2001 ACE: great uncertainty IMP8: first peak is not observed at high E SOHO: strong saturation at high E

23. TRAD, Tests & Radiations 23 ESWW11-session 5, November 18, 2014Conclusions  ACE/SIS data  A lot of cleaning work has been performed on the ACE/SIS He data but still for some large events data cannot be trusted.  ACE/SIS heavier ion data are in better shape except for some high energy data which are uncertain.  Alternative He dataset for ion abundance calculation  SOHO/ERNE HED data show important saturation effects.  IMP8/GEM data show important data gaps.  GOES is the best candidate  Very nice overlap with ACE/SIS data during smaller SEP events.  High energy points to be ignored when only background (smaller events).

24. TRAD, Tests & Radiations 24 ESWW11-session 5, November 18, 2014Conclusions  Perspectives  Compare ACE/SIS Z>2 ion data with other available datasets: Wind, SOHO.  Complete and validate the solar ion abundance ratio calculation [come see poster on session 8 tomorrow]. Valuable help has been provided by the ACE/SIS team, the SOHO/ERNE team and A. Tylka.