Subsurface Horizontal Flows During Solar Cycles 24 and 25 with Large-Tile Ring-Diagram Analysis

Solar Physics ◽  
2021 ◽  
Vol 296 (12) ◽  
Author(s):  
R. Komm
1997 ◽  
Vol 485 (2) ◽  
pp. 869-874 ◽  
Author(s):  
J. Patron ◽  
I. Gonzalez Hernandez ◽  
Dean‐Yi Chou ◽  
M.‐T. Sun ◽  
T.‐M. Mu ◽  
...  

2011 ◽  
Vol 271 ◽  
pp. 012008 ◽  
Author(s):  
R S Bogart ◽  
C Baldner ◽  
S Basu ◽  
D A Haber ◽  
M C Rabello-Soares

2001 ◽  
Vol 563 (1) ◽  
pp. 410-418 ◽  
Author(s):  
S. P. Rajaguru ◽  
Sarbani Basu ◽  
H. M. Antia

2004 ◽  
Vol 610 (2) ◽  
pp. 1157-1168 ◽  
Author(s):  
Sarbani Basu ◽  
H. M. Antia ◽  
Richard S. Bogart

2013 ◽  
Vol 440 ◽  
pp. 012027 ◽  
Author(s):  
Olga Burtseva ◽  
Sushant Tripathy ◽  
Richard Bogart ◽  
Kiran Jain ◽  
Rachel Howe ◽  
...  

2019 ◽  
Vol 626 ◽  
pp. A3 ◽  
Author(s):  
Zhi-Chao Liang ◽  
Laurent Gizon ◽  
Aaron C. Birch ◽  
Thomas L. Duvall

Context. Solar Rossby waves (r modes) have recently been discovered in the near-surface horizontal flow field using the techniques of granulation-tracking and ring-diagram analysis applied to six years of SDO/HMI data. Aims. Here we apply time-distance helioseismology to the combined SOHO/MDI and SDO/HMI data sets, which cover 21 years of observations from May 1996 to April 2017. The goal of this study is to provide an independent confirmation over two solar cycles and in deeper layers of the Sun. Methods. We have measured south-north helioseismic travel times along the equator, which are sensitive to subsurface north-south flows. To reduce noise, the travel times were averaged over travel distances from 6° to 30°; the mean distance corresponds to a p-mode lower turning point of 0.91 R⊙. The 21-year time series of travel-time measurements was split into three seven-year subsets and transformed to obtain power spectra in a corotating frame. Results. The power spectra all show peaks near the frequencies of the classical sectoral Rossby waves for azimuthal wavenumbers in the range 3 ≤ m ≤ 15. The mode frequencies and linewidths of the modes with m ≤ 9 are consistent with a previous study whereas modes with m ≥ 10 are shifted toward less negative frequencies by 10–20 nHz. While most of these modes have e-folding lifetimes on the order of a few months, the longest lived mode, m = 3, has an e-folding lifetime of more than one year. For each mode, the rms velocity at the equator is in the range of 1–3 m s−1, with the largest values for m ∼ 10. No evidence for the m = 2 sectoral mode is found in the power spectrum, implying that the rms velocity of this mode is below ∼0.5 m s−1. Conclusions. This work confirms the existence of equatorial global Rossby waves in the solar interior over the past two solar cycles and shows that time-distance helioseismology is a promising technique to study them deep in the convection zone.


Author(s):  
Richard S. Bogart ◽  
Sarbani Basu ◽  
Maria Cristina Rabello-Soares ◽  
H. M. Antia

Solar Physics ◽  
2012 ◽  
Vol 287 (1-2) ◽  
pp. 57-69 ◽  
Author(s):  
C. S. Baldner ◽  
S. Basu ◽  
R. S. Bogart ◽  
O. Burtseva ◽  
I. González Hernández ◽  
...  

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