1. Takashi Sakurai National Astronomical Observatory of Japan
Summary-2 (?)
Takashi Sakurai
National Astronomical Observatory of Japan

2. Two Summaries: Two Basic Problems in Solar MHD
Parker’s Hypothesis  coronal heating (nanoflare theory)
Aly&Sturrock’s Hypothesis  CME

3. Parker Problem and Parker’s Hypothesis
uniform initial field
regular boundary motion (but not preserving winding pattern)
creates discontinuity
leads to dissipation (by reconnection)

4. Parker: ApJ 174, 499, 1972

5. Parker: ApJ 264, 635, 1983

6. Parker: Solar Phys. 121, 271, 1989

7. Ideal MHD magnetic field boundary motion create discontinuity? uniform
singular
yes
discontinuity
regular
with nulls
dipping field lines no

8. Parker: ApJ 407, 342, 1993
discontinuous field
regular motion

9. magnetic null and singular mapping
dipping field lines and singular mapping

10. Mikic, Schnack, and van Hoven: ApJ 338, 1148, 1989

11. Discontinuity is not created.
See also Galsgaard and Nordlund, JGR 1996 Craig and Sneid, Solar Phys., in press

12. real life (with finite resistivity)
uniform field, regular boundary motion
nulls created by diffusion
singular mapping of field lines
shear layer is created
dissipation by reconnection

13. Dennis: Solar Phys. 100, 465, 1985

14. Shimizu, PASJ 47, , 1995

15. N(E) E limited by micro physics
small scale events slope< −2 ? new physics
“flare” population slope ~ −1.5
limited by finite size of the sun E
1026 erg
1032 erg

16. Aschwanden: Solar Phys. 190, 223, 1999
Arbitrarily small flare loops cannot exist.

17. What is “new physics?” purely coronal events? no conduction loss
new regime of reconnection?
new component of magnetic field?
new component of driving motion?
????
forget this and go to waves?

18. Aly&Sturrock’s Hypothesis
closed field lines (loops)+footpoint motion
energy increases and asymptotically approaches an upper limit
the upper limit is attained by the open field
the energy of the closed field can never exceed the open field energy
hence eruption to the open field is impossible

20. Exceptions two interacting flux tubes (Choe and Cheng 2002)
configuration with a detached flux tube (a filament) (Li and Hu 2003)

21. Choe and Cheng: ApJ, 574, L179, 2002

23. I wonder if the existence of a field-free volume separating the two flux tubes is essential.
Can more general conditions be formulated to obtain E>Eopen?

24. Li and Hu: Chinese J. Astron. Astrophys. 3, 555, 2003
Field with floating flux rope has energy exceeding the open field energy.
In this case the excess is 1.5% of open field, 2.4% of closed dipole field energy.

25. Y.Q.Hu: ApJ 607, 1032, 2004
octapole field
central arcade opens, asymptotically approaching partially open field

26. Y.Z.Zhang et al.: ApJ 626, 1096, 2005
With floating flux rope, the open field energy is exceeded

28. Three Major Problems in Solar Physics
flares and CMEs
Solar-B launch in activity minimum,,,
high resolution, trigger mechanism
heating of the atmosphere (and solar-wind acceleration)
waves or superposition of small explosions?
the main target of Solar-B
carefully-designed observing plans (not trivial)
magnetic field generation (dynamo)
important hints (diffusion, surface dynamo,,,)