1. SPD 2004 Peter T Gallagher (NASA/GSFC) The Active Region Evolution and Activity of Halloween 2003 Peter T. Gallagher (L-3 Com GSI) and R. T. James McAteer (NRC) at NASA Goddard Space Flight Center

2. SPD 2004 Peter T Gallagher (NASA/GSFC) 18 Oct - 4 Nov, 2003 Activity Overview oIn 17 days there were: o3 of the largest regions of cycle 23. oOne of the largest regions in recorded history. o3  -ray line flares observed by RHESSI. o12 X-class flares. oX28+, X17.2, and an X10. o41 M-class flares. o62 C-class flares. oAt least 15 “halo” CMEs. o~5 days of enhanced >100 MeV protons. X17.2 X10.0 X8.3

3. SPD 2004 Peter T Gallagher (NASA/GSFC) NOAA 10484: Summary oDates observed: 18 - 29 Oct (11 days) oMaximum area: 1940  h at ~W01 (23 Oct) oHale/Mount Wilson Class:  oMcIntosh Class: Ekc oMaximum number of spots: 53 oFlare numbers: 30 C-class, 14 M-class, 2 X-class oFlare rates (flares/day): 2.73 (C-class), 1.27 (M-class), 0.18 (X-class)

4. SPD 2004 Peter T Gallagher (NASA/GSFC) NOAA 10486: Summary oDates observed: 23 Oct - 4 Nov (12 days) oMaximum area: 2680  h at ~W25 (30 Oct) oHale/Mount Wilson Class:  oMcIntosh Class: Fkc oMaximum number of spots: 94 oFlare numbers: 15 C-class, 20 M-class, 8 X-class and 3  -ray oFlare rates (flares/day): 1.25 (C-class), 1.66 (M-class), 0.66 (X-class)

5. SPD 2004 Peter T Gallagher (NASA/GSFC) NOAA 10488: Summary oDates observed: 26 Oct - 4 Nov (9 days) oMaximum area: 1830  h at ~W30 (30 Oct) oHale/Mount Wilson Class:  oMcIntosh Class: Fkc oMaximum number of spots: 61 oFlare numbers: 17 C-class, 7 M-class, 2 X-class oFlare rates (flares/day): 1.88 (C-class), 0.77 (M-class), 0.22 (X-class)

6. SPD 2004 Peter T Gallagher (NASA/GSFC) The Active Regions of Oct-Nov 2003

7. SPD 2004 Peter T Gallagher (NASA/GSFC) GOES X-rays Notable Events: o18 Oct - 4 Nov oX17.2 (28 Oct) oX10.0 (29 Oct) oX8.3 (2 Nov) oX28+ (4 Nov)

8. SPD 2004 Peter T Gallagher (NASA/GSFC) GOES Protons oFirst >100 MeV increase from X1.2 on Oct 26 (NOAA 10484 at ~W38). oAll >100 MeV increase from regions with E08 < Lon < W90. o4 proton events from NOAA 10486 at: oE08 (X17.2 28 Oct) oW02 (X10.0 29 Oct) oW56 (X8.3 2 Nov) o W90 (X28 4 Nov).

9. SPD 2004 Peter T Gallagher (NASA/GSFC) The X-rated Details oFrom http://beauty.nascom.nasa.gov/~ptg/oct-nov-2003-xflares.html W70 < Lon < W90 E08 < Lon < W70 E90 < Lon < E08

10. SPD 2004 Peter T Gallagher (NASA/GSFC) Sun-Earth Connectivity oAssume Parker spiral of form: oSee a space weather report for Mars at http://beauty.nascom.nasa.gov/~ptg/mars

11. SPD 2004 Peter T Gallagher (NASA/GSFC) NOAA 10484 oX1.1 (19 Oct) / X1.2 (26 Oct)

12. SPD 2004 Peter T Gallagher (NASA/GSFC) NOAA 10486 oX17.2 (28 Oct) / X10.0 (29 Oct) / X8.3 (2 Nov) / X28 (4 Nov)

13. SPD 2004 Peter T Gallagher (NASA/GSFC) NOAA 10488 oX3.7 and X2.9 (3 Nov)

14. SPD 2004 Peter T Gallagher (NASA/GSFC) RHESSI Flare Locations: NOAA 0484

15. SPD 2004 Peter T Gallagher (NASA/GSFC) RHEESI Flare Locations: NOAA 0486

16. SPD 2004 Peter T Gallagher (NASA/GSFC) RHESSI Flare Locations: NOAA 0488

17. SPD 2004 Peter T Gallagher (NASA/GSFC) Magnetic Flux Changes oNOAA 10484 oB + decays slowly. oB - increases then decays. oNOAA 10486 oGrowth in B + until central meridian, then decay. oGrowth in B - until central meridian, then remains constant. oB - shows rapid change during X17.2. oNOAA 10488 oRapid growth in B + and B - over 2- days.

18. SPD 2004 Peter T Gallagher (NASA/GSFC) Polarity Balance oNOAA 10484 oB - > B + oB + ~ const odB - /dt > 0 oNOAA 10486 oB + > B - then B + < B - odB - /dt > 0 oNOAA 10488 oB + > B - odB + /dt > dB - /dt X17.2

19. SPD 2004 Peter T Gallagher (NASA/GSFC) oConverging photospheric flows sweep opposite polarity fields towards the neutral line of the  (bipolar groups do NOT form significant neutral lines, transverse gradients, and hence flares). oLarge transverse gradients in the photospheric magnetic field are observed across the neutral line of large  spots (Patty & Hagyard, 1986; Zhang et al., 1994). oOver a period of hours, the continued concentration of opposite polarities in a relatively small area leads to strong transverse gradients (Gallagher, Moon, & Wang 2002). o  energy_buldup (hrs - days) >>  energy_resease (secs - mins) oAn instability in the corona results in the release of stored (Priest & Forbes; Antiochos et al.) Horizontal Gradient

20. SPD 2004 Peter T Gallagher (NASA/GSFC) NOAA 10484 oAutomated neutral line and gradient measurements. oLarge field gradients observed across multiple neutral lines. oX1.1 (19 Oct) oX1.2 (26 Oct)

21. SPD 2004 Peter T Gallagher (NASA/GSFC) NOAA 10486 oStrong transverse gradients in B los. oMultiple long and complex neutral lines. oX17.2 (28 Oct) oX10.0 (29 Oct) oX8.3 (2 Nov)

22. SPD 2004 Peter T Gallagher (NASA/GSFC) NOAA 10488 oShort neutral lines. oStrong gradients. oX2.7 (3 Nov). oX3.9 (3 Nov).

23. SPD 2004 Peter T Gallagher (NASA/GSFC) Size Distribution of Sunspot Groups (1900-2000) oMaximum areas: oNOAA 10484 = 1940  h oNOAA 10486 = 2680  h oNOAA 10488 = 1830  h NOAA 10484 NOAA 10488 NOAA 10486

24. SPD 2004 Peter T Gallagher (NASA/GSFC) Size Distribution of Sunspot Groups (1874-2003) oNOAA 10486: in largest 5% of regions oNOAA 10484 and 10488: in largest 24% of regions

25. SPD 2004 Peter T Gallagher (NASA/GSFC) Area, Class and Activity oSammis et al., ApJ, 540, 583, (2000) o2789 active regions (1989-1997) oAll flares above X4 come from 11  regions with areas >1000  h. X28! NOAA 0486 X M C B

26. SPD 2004 Peter T Gallagher (NASA/GSFC) oSOHO EIT 19.5 nm (18 Oct - 5 Nov)

27. SPD 2004 Peter T Gallagher (NASA/GSFC) Summary oAll three regions were large (ie, >1500  h), multipolar (ie, magnetically complex), highly dynamic (ie, changing flux distribution), with strong gradients (ie, > 50 G/Mm) and long neutral lines (ie, >60 Mm): magnetic properties essential to flare and CME production. oNOAA 10486 was particularly unusual in terms of its size, complexity, and activity. One of the largest and most active regions in the past 100-years. oDoes the formation of these region at such a late stage in the solar cycle provides evidence for nonlinear dynamo action? oDoes the emergence of several regions imply the regions resulted from global rather than local effects? oMuch work still to be done to understand the relationship between the field configuration in the photosphere with the activity observed in the corona.