1. The Rise of Solar Cycle 24: Magnetic Fields from the Dynamo through the Photosphere and Corona and Connecting to the Heliosphere
Part 1:
Interior and Photosphere

2. Subsurface Flows:
Torsional Oscillation (east-west)
variation from the mean differential rotation
very small signal
related to the timing of the cycle
Meridional Flow (north-south)
important for the timing of the cycle
Frank Hill: observations
Mark Miesch : modeling interpretation

3. Torsional oscillation at a depth of 7 Mm
Cycle 25??? 2019?-2030?
Cycle 23 ( )
Equatorward Branch
Cycle 24 ( ?)
Poleward branch Equatorward branch
5 m/s
-5 m/s
No sign yet of poleward branch flow for Cycle 25.
May mean that Cycle 25 will not start until at least 2023

4. M. Rempel suggested that the non-appearance of the
high-latitude branch may be due to a change in the differential rotation profile that arises from a reduction of the  effect
Strong cycles have more rigid differential rotation
(magnetic tension tends to reduce rotation shear)
Weak cycles rotate more differentially, i.e. poles
slow down BUT
Plot had a mean differential rotation subtracted
this may mask poleward branch
This hypothesis can be tested
Stay tuned for the next NSO press release !!!

5. Meridional Flow
At the Surface: both heliosesimology and correlation tracking
techniques show it poleward + AR band modulation
hard to measure at high latitudes
multiple cells in latitude
faster (1-2 m/s) flow near surface during recent minimum
Deep meridional flow:
hard to measure
issues with data inversions
seems to increase with depth
complex cell
return flow not detected

6. In contrast, using correlation tracking techniques : David Hathaway finds that the meridional flow decreases with depth and there is a shallow return flow
R. Komm: reliable technique but no agreement on interpretation (longer time scales do not necessarily
mean longer-lived cells)
data may not indicate a shallow return flow!
What is important for the dynamo model is the return
flow at the bottom of the convection zone which has
not been detected yet
Consensus:
We do not know much about meridional flow,
especially its variation with depth

7. magnetic flux emergence
Gordon Petrie:
magnetic flux emergence
first spot Jan 2008
30deg latitude

8. strong recovery after very deep minimum current activity
Number of images with fields stronger than 1 kG
Cycle Cycle Cycle Cycle 24
strong recovery
after very
deep minimum
current activity
level <50% of
Cycle maxima
in terms of maximum
field strength

9. magnetic butterfly covering 37 years of NSO data !!!
long minimum
Cycle Cycle Cycle Cycle 24
hemispheric asymmetry: south more active at the end of cycle 23
north more active at the start of cycle 24, still more active now
not seen in the preceding cycles but cycle 20 shows noticeable asymmetry

10. POLAR MAGNETIC FIELDS
weak polar magnetic fields (consistent with the observed decrease in open flux in the heliosphere)
A. Munoz-Jaramillo: how important are polar fields for the dynamo?
Are they a by-product or the seeds for the next cycle(s)?
This is also important for the heliosphere-dynamo connection

11. Doug Biesecker: challenged the observational evidence
that we are entering a Maunder Minimum
Weakening Magnetic Fields in Sunspot
What was in the press release
The raw data presented at Space Weather Workshop 2010
no obvious reason that a straight line is the appropriate fit
to these data. A curve that follows the solar cycle may
in fact provide a better reduced chi square.
Solar Max
Solar Min

12. The slowing ‘rush to the poles’
Cycle 24 started ‘late.’ Cycle 23 was 12 years long, 2 years longer than
the previous two cycles. Iron emission seems to appear right as expected,
12 years after the last one
Cycle 21
(10.3 yrs)
Cycle 22
(10.0 yrs)
Cycle 23
(12.2 yrs)

13. The Rise of Solar Cycle 24
Part 2:
Corona & Heliosphere
9:45-11:00:
polar fields (Dick Altrock)
11:30-12:45:
open flux
(Janet Luhmann & Nathan Schwadron)
14:00-17:00:
open flux & heliosphere (cont.)

14. The Rise of Solar Cycle 24
Part 2:
Corona & Heliosphere
we will be in room Cabaret today
we hope you will join us!