Session H 10 Solar Cycle Dynamo Friday 10

Session H 10 Solar Cycle & Dynamo Friday, 10: 30 - Noon Feb. 17, 2006 Komm & Hoeksema

H 10: Solar Cycle & Dynamo • Introduction by Rudi outlining purpose • Rachel on long-term global helioseismology results, challenges and opportunities. Q&A: Unclear how hard high-l will be. Longer time series and increased continuity are the main contributions of HMI.

H 10: Solar Cycle & Dynamo • Tom Duvall on local seismology results, challenges and opportunities. Some from Giles thesis. Return flow hard – put in as continuity constraint by Giles. Tom’s relook still shows some anomalies. May be a feature of MDI. This topic is something that seems to fall between the cracks. Meridional flows are key to progress.

H 10: Solar Cycle & Dynamo • Mark Miesch about dynamos and how helioseismology can help constrain them. He described eight specific questions. • Q&A: How to determine whether helicity is conserved? Magnetic data may provide a path to answer. Where does dynamo reside? Still not certain – controversial suggestion that it operates throughout CZ. Is there a global scale flow associated with tipped bands in Q 4 model? Yes some, mostly on 2 D shells, largely zonal. Tom quotes some results suggesting a signal in m>=1 (non-zonal) modes. Aimee reports similar in sunspot records (with Gilman). What is scale of shears and such? Can HS resolve it? E. g. downflows are important and more intense in giant cells, but small. Larger scale may be more possible to see. • How to get dynamo and HS folks working together? No immediate volunteers, but a true working group might be useful. Maybe in association with another meeting.

H 10: Solar Cycle & Dynamo • Contributed – Sarbani on tachocline temporal and spatial dependence. Question about how effects at the surface are handled or other systematics recognized. Current results are mostly done without much accommodation – the expectation is that to first order they come out in differencing during the analysis. • Contributed – Aaron Birch on deep focus Time-Distance seismology. Coming back to some older work with Tom and Sasha. What is time horizon for more progress? Charlie & Doug working on new spherical code – may not solve all problems though. Probably longterm project. • Rachel – invite some theorists to next Lo. HCo meeting – but Boulder would be good. General support. Mark M, Juri, Rudi. Laurent? There’s a meeting in Potsdam next April 2007 on dynamos. Report some results at LWS-1 next spring. Maybe something this fall in Boulder. Organizers will propose a date or two.