Tag Archives: torsional oscillation

223. Helioseismic evidence that the solar dynamo originates near the tachocline

Contributed by Krishnendu Mandal. Posted on February 26, 2026

Helioseismic analysis of solar torsional oscillations reveals dynamo-wave–like signatures that originate near the tachocline and propagate through the convection zone, linking internal zonal flows to the surface magnetic cycle. Additional evidence from frequency-splitting coefficients and rotational shear variations shows strong solar-cycle correlations, supporting the tachocline as a primary site of solar dynamo action.

203. Exploring Substructure of the Near-Surface Shear Layer of the Sun

Contributed by Cristina Rabello Soares. Posted on October 4, 2024

The Sun’s near surface shear layer (NSSL) is characterized by using HMI ring-diagram results. It is found the NSSL is composed of three distinct layers: a deeper larger region with a small shear, a narrow middle layer with a strong shear, and a layer very close to the surface.

118. Detection of Dynamo Waves inside the Sun

Contributed by Alexander G. Kosovichev. Posted on January 15, 2019

An analysis of zonal flow acceleration/deceleration inside the Sun reveals patterns of dynamo waves, and suggests that the primary seat of the dynamo is located in a high-latitude zone of the tachocline.

108. Signatures of Solar Cycle 25 in Subsurface Zonal Flows

Contributed by Rachel Howe. Posted on August 3, 2018

New helioseismic analysis of the Sun’s subsurface zonal flows shows the equator-migrating branch of the faster-than-average rotation, a sign of the Solar Cycle 25.

20. Solar Meridional Flow in the Shallow Interior during the Rising Phase of Cycle 24

Contributed by Junwei Zhao. Posted on June 18, 2014

Subsurface meridional flow speed shows an anti-correlation with the magnetic flux being transported poleward above the latitude of 35&#176. In the lower latitude, the residual meridional flow, after a long-time mean profile is subtracted, shows converging flow toward the activity belts.