1. RHESSI and global models of flares and CMEs: What is the status of the implosion conjecture? H.S. Hudson Space Sciences Lab, UC Berkeley

2. Potsdam 4 September 2008 2/19 A TRACE movie that shows everything

3. Potsdam 4 September 2008 3/19 Field change and implosion Hudson 2000 Sudol-Harvey 2005 2 Nov. 2003 flare cf Kosovichev & Zharkova 1999; Wang et al. 2002 Liu et al. 2005 2.5’’ 24 min Fields Isomagnetobars

4. Potsdam 4 September 2008 4/19 High-energy state: same boundary B n, but a larger volume Low-energy state Field expansion and total stored energy (cf. Aly conjecture)

5. Potsdam 4 September 2008 5/19 High-energy state: same boundary B n, but a larger volume Low-energy state Field expansion and total stored energy (cf. Aly conjecture)

6. Potsdam 4 September 2008 6/19 J. Lee via FASR Something like isomagnetobars

7. Potsdam 4 September 2008 7/19 Magnetoisobars, Models, and FASR The deformation of the magnetoisobars by a flare determines the energy sources This can be done in via extrapolation from magnetograms FASR can observe level surfaces of |B|, which (though not B 2 ) can provide the crucial information

8. Potsdam 4 September 2008 8/19 Sui & Holman, ApJ 596, L251 (2003) Sui et al., ApJ 612, 546 (2004) Holman et al. Unpublished (2005) Veronig et al., A&A 446, 675 (2006) Ji et al., ApJ 660, 893 (2007) Ji et al., ApJ 680, 734 (2008) RHESSI and downward motions

9. Potsdam 4 September 2008 9/19 RHESSI observes the implosion? Sui & Holman 2003

10. Potsdam 4 September 2008 10/19 RHESSI observes the implosion? Veronig et al 2006 3 November 2003

11. Potsdam 4 September 2008 11/19 The standard flare cartoon implies “shrinkage” (e.g. Svestka et al., 1982) In the magnetosphere this is “dipolarization” Such effects are consistent with magnetic implosion as a source of energy Other effects (converging or “unshearing” FP motions, sunspot/penumbral effects) are likely to be physically related About shrinkage

12. Potsdam 4 September 2008 12/19 Magnetic energy storage Integral distribution of stored energy (NLFFF vs potential) in height (cf. Regnier & Priest, 2007). Need to find locus of B 2 /8  Have force-free condition Curl(B) =  (x,y)B Extrapolation of photospheric field observations - Potential (  = 0) - Linear force-free (  constant) - Non-linear force-free NLFFF (  general) B los in a solar active region and the 50% contour of B 2

13. Potsdam 4 September 2008 13/19 NLFFF modeling Schrijver et al. 2008 Before X3.4 After X3.4

14. Potsdam 4 September 2008 14/19 Magnetic energy storage “Vertically integrated” electrical currents in an active region before (a) and after (b) an X-class flare (Schrijver et al., 2008). Note the apparent organization into a flux rope. The magnetic energy in an active region is stored at low altitudes and may reside in a filament channel. Spot Problem?

15. Potsdam 4 September 2008 15/19 25-50 keV White light Thick target energetics / beam fluxes 1 px = 0.5” ~ 350 km White light footpoint area ~ 10 17 cm 2 In thick-target theory, can use HXR photon spectrum to calculate parent electron spectrum in chromosphere (Brown 1971). The inferred requirement on electron number is - 10 34 -10 36 electrons s -1 (ie coronal volume of 10 27 cm 3, n = 10 9 e - cm -3 should be emptied in ~10s) Beam density can be inferred using white-light footpoint areas as a proxy for beam ‘area’.

16. Potsdam 4 September 2008 16/19 Problems for coronal acceleration Location (fast shock A, slow shock B, current sheet C - are any of these real?) The “number problem” - where to get the particles? How to get “flare particles” into the heliosphere? Beam dynamics - return currents and inductive effects Hear Lyndsay’s talk A B C

17. Potsdam 4 September 2008 17/19 Fletcher & Hudson 2008 http://solarmuri.ssl.berkeley.edu/~hhudson/cartoons/ New ideas outside ideal MHD

18. Potsdam 4 September 2008 18/19 Magnetic Implosion still seems to make sense for flare/CME excitation This is not inconsistent with large-scale reconnection flows, and modeling shows the Poynting flux to have attractive properties The source energy is at low altitudes and may be associated with simple large-scale currents Conclusions

19. Potsdam 4 September 2008 19/19 Magnetic Implosion still seems to make sense for flare/CME excitation This is not inconsistent with large-scale reconnection flows, and modeling shows the Poynting flux to have attractive properties The source energy is at low altitudes and may be associated with simple large-scale currents To solve a crime, “follow the money”; to solve a flare, “follow the energy”! Conclusions

20. Potsdam 4 September 2008 20/19 Energy conversion (non-thermal) HXRs, UV, WL chromosphere electron beam “Caixa preta” Spukhaftig non-locality

21. Potsdam 4 September 2008 21/19 An IR movie from the “opacity minimum” Xu et al. 2005

22. Potsdam 4 September 2008 22/19 Energy conversion (thermal) J. Birn 2008

23. Potsdam 4 September 2008 23/19 Incoming Poynting fluxUp & down Poynting fluxUp & down enthalpy fluxUp & down kin. energy flux Enthalpy flux H = (u+p) v = 2.5 p v Poynting flux S = E  B Kin. energy flux K = 0.5  v 2 v 3D simulations by J. Birn, 2008 (medium beta case) Energy conversion (thermal)