Subsurface Flows from ring-diagram analysis Irene González Hernández National Solar Observatory Tucson, Arizona

Subsurface flows from ring-diagram analysis  Ring-diagrams technique  Differential rotation  Meridional circulation  Dynamics of active regions and filaments  Results at different heights  Future work and conclusions

Ring-diagrams technique  Hill, F; 1988, ApJ,333,996  Patrón, J.; Hill, F.;Rhodes, E.J.,Jr.;Korzennik,S. G. and Cacciani,A., 1995, ApJ, 455, o 1664 min  Gonzá l ez Herná n dez, I.; 1998 PhD tesis, University of La Laguna  Gonzá l ez Herná n dez, I.; Patrón,J.; Roca Cortés, T.; Bogart, R.S.; Hill, F.; Rhodes,E.J.,Jr.,2000, ApJ

Flows from rings: synoptic maps Courtesy of R. Komm

Differential Rotation Radial variation of the mean rotation rate, shifted to give a zero rate at the surface, for global inversions (curves mark error bounds) of MDI data and local inversions of MDI (filled circles) and GONG (open diamonds) data at latitudes 0(top left), 15(top right), 30 (bottom left) and 45 (bottom right). Howe, R. et al., 2006, Solar Physics,235,1.

Zonal torsional oscillation Howe, R. et al., 2006, Solar Physics, 235,1. Zonal flow residuals from global helioseismology and local helioseismology (ring-diagrams) at 0.99Rsun

North-South asymmetry  The latitudinal variation is most likely a consequence of the solar-cycle variation of the zonal flow, the torsional oscillation pattern.  The zonal flow is predominantly faster in the southern hemisphere that in the northern one. This differences increase with latitude about 25-degrees, and with depth. Zaatri, A. et al, 2006, Solar Physics, 236,227 Temporal variation of the zonal flow in the Northern (dark grey) and Southern (light grey) hemisphere at four latitudes and four depths. The surface rotation rate has been subtracted (Snodgrass, 1984). The line thickness represents about two standard deviations of the formal undertainty. The top row shows, for comparison, the time scale in Carrington Rotations.

Meridional Circulation and Dynamo Models  Dikpati, Mausumi; Gilman, Peter A. "Flux-Transport Dynamos with α -Effect from Global Instability of Tachocline Differential Rotation: A Solution for Magnetic Parity Selection in the Sun". 2001, ApJ, 559, 428  Gilman, P.A and Miesch, M. "Limits to Penetration of Meridional Circulation Below the Solar Convection Zone“, 2004, ApJ, 611, 568.  Giles, P., 2000, PhD Thesis, Stanford University.  Haber, Deborah A.; Hindman, Bradley W.; Toomre, Juri; Bogart, Richard S.; Larsen, Rasmus M.; Hill, Frank. "Evolving Submerged Meridional Circulation Cells within the Upper Convection Zone Revealed by Ring-Diagram Analysis". 2002, ApJ,570, 855  McDonald, E.; Dikpati, M. "Evolution of Large-scale Solar Magnetic Fields in the Presence of a Multi-cell Meridional Flow". 2004,American Astronomical Society Meeting 204, #53.06 Courtesy of E. McDonald

A quick history of Meridional Circulation from rings  González Hernández, I, Patr ό n, J, Bogart, R. S. and the SOI Ring Diagram Team, 1999, ApJ 510, L153  Basu, S. and Antia, H.M, 2002 Proceedings of the SOHO 11 Symposium  2003, ApJ 585, 553  Haber, D.A., Hindman, B. W.,Toomre, J., Bogart, R.S., Larsen, R.M., Hill, F.,2002, ApJ 570, 855.  González Hernández, I., Komm, R.,Hill,F.,Howe,R., Corbard, T. and Haber, D.A., 2006, ApJ 638, 576  Zaatri, A., Komm,R., Gonzalez Hernandez, I., Howe, R. and Corbard, T., 2006, SoPh 236, 227

Meridional Circulation Basu & Antia, 2003

Meridional Circulation Haber et al, 2002

Meridional Circulation González Hernández et al, 2006

Meridional Circulation González Hernández et al, 2006

Meridional Circulation Zaatri et al, 2006

Meridional Circulation Zaatri et al, 2006

Recent results from MDI Haber, D. et al., 2006

Recent results from GONG++

Meridional Circulation from small patches Courtesy of B. Hindman and D. Haber

Subsurface flows and their relation to surface magnetic activity NOAA10069: 300 o Longitude, −7.5 o Latitude Courtesy of R. Komm

Flows in filaments Daily high-resolution flow maps obtained using 4 ｡ - diameter tiles. The maps span four consecutive days: (a) 2002 March 30, (b) 2002 March 31, (c) 2002 April 1, and (d) 2002 April 2. Regions of opposite magnetic polarity, as determined from MDI magnetograms, are indicated in green and red. The dark contour line shows the position of a filament as observed in BBSO H images. On March 31when BBSO images were unavailable, the contour from the previous day is indicated with a dashed line. Four long-lived convection cells span the location of the filament and are marked with numerals I ﾐ IV (in white). The filament runs through the center of these cells and the apparent flow along the neutral line is complicated. The widening of the filament over the span of the four days is probably due to projection of the filament against the solar disk as the region rotates across the Sun's visible surface. Hindman, B., Haber, D. and Toomre, J. ApJ, 2006, 653, 725

Flows in filaments Daily high-resolution flow maps obtained using 2 ｡ - diameter tiles, zoomed in to cover the region outlined with the white dashed box in previous fig. The maps span the same four days displayed in the previous fig: (a) 2002 March 30, (b) 2002 March 31, (c) 2002 April 1, and (d) 2002 April 2. The finer resolution available in these maps indicate that there is a complex interaction between the flow cells and photospheric magnetism. Hindman, B., Haber, D. and Toomre, J. ApJ, 2006, 653, 725

Flows at different heights Subsurface flow maps for Jan 18, 2003(left) and Jan 19, 2003 (right). Blue arrows show flows obtained from the Ni line and red from the K line. Differences Jain, K. et al, 2006

Flows from untracked regions Courtesy of R Bogart, C Rabello-Soares and S. Basu

Flows from untracked regions Courtesy of R Bogart, C Rabello-Soares and S. Basu

The future  GONG/MDI  3-Dimensional inversions  Large scale flows:  Foreshortening / Projection  Other high latitude effects  Flows in active areas  Effect of magnetic activity  fitting method  More analysis  HMI (Solar Dynamics Observatory)  VIM (Solar Orbiter)

Ring analysis has made a significant contribution to the study of large scale flows from the surface to approx. 30Mm. New results confirm the solar cycle dependence of meridional circulation close to the surface found by previous works, but show almost no dependence at deeper layers. Surface activity effect is being investigated. Multi-cell circulation needs to be confirmed HRRA: Flows in active regions and filaments Several problems of the technique need to be addressed We are limited in latitude to +/- 50 degrees Higher resolution observations (HMI) Observations off the ecliptic (Solar Orbiter mission) The stellar connection: “Try to use dynamo models that do “well” in the solar case” (M. Rempel) Conclusions