2. Homology tutorial Hugh Hudson Solar MURI 21-Nov-03

3. Definition: Homology is the tendency for event morphology to repeat precisely. Comment: Here morphology means anything at all: image, time series, spectrum, location…

4. Trevisan et al., RMA&A 21, 557, 1990 HH

5. Cliver & Wefer, Solar Phys. 71, 39, 1981 Microwaves

6. TRACE 24 October 2003 15:17 24 October 2003 22:02 K. Schrijver, 20-Nov-03

7. Yohkoh spiky arcades

8. Morita et al., Solar Phys. 200, 137, 2001 Yohkoh “candle flame”

9. Bastille Day?

10. Processes in which the entropy of an isolated system would decrease do not occur, or, in every process taking place in an isolated system, the entropy of the system either increases or remains constant Second law of thermodynamics Solar application An eruption (e.g., a CME) proceeds irreversibly because Of energy dissipation (e.g., through reconnection or shock waves

11. Common knowledge Ranns et al., A&A 360, 1173 (2000) Nitta & Hudson, GRL 28, 3801 (2001) Emerging flux leads to near-homology Comment This explanation for homologous flares implies some persistence in the flux emergence, ie a coherence over time scales of the interval of homology

12. Heyvaerts, Priest & Rust, ApJ 216, 123, 1977 Standard emerging- flux cartoon Note the poor cartoonsmanship - the panels show different field lines

13. The flow associated with flux emergence implies changes in the footpoint geometry. Successive events would have different coronal null geometries. The separatrix current in this geometry circulates only in the corona.

14. Nitta & Hudson, GRL 28, 3801 (2001)

15. Soft X-rays, hard X-rays

16. Magnetism (MDI), hard X-rays (HXT), soft X-rays (SXT)

17. Emerging flux time-history

18. Chertok et al., JGR to be published (2003? 2004?)

19. Homologous dimmings

20. Dimmings at various wavelengths

22. Conclusions Homologous flares might be explainable by persistent flux emergence, even in a reconnection model Homologous CMEs might be explained similarly, if they are basically derived from small spatial scales in ARs Chertok et al dash that hope, though, because the homology extends to the quiet corona on large scales, with dissipation