Meridional flows in the solar interior

December 03, 2019
Solar and Stellar Interiors

Using SDO/HMI observations to infer the subsurface meridional flow

The Sun's global magnetic field is thought to be maintained by large-scale plasma flows in the interior: rotation and meridional circulation.  Solar interior rotation has been well-measured by global helioseismology.  Meridional flow is inaccessible by traditional global helioseismology but is a very important target for local helioseismology.

This project is to carefully measure wave travel times on the sun in order to extract and characterize the signals due to meridional circulation and rotation. Rotation provides an important validation test as it is well known by global helioseismology. Particular attention will be paid to estimates of the random noise in the meridional flow and rotation measurements as well as magnetic and systematics effects. A goal is to provide clean observations for inversions of travel times and to measure the solar-cycle variations of the meridional flow.

An example model for the meridional flow in the convection zone.  At the surface, the flow is from the equator to the poles, and the return flow is at the base of the convection zone.  In this project, time-distance helioseismology will be used to determine the actual meridional flow in the Sun, and to measure the time variations of this flow   (image from the PhD Thesis of Peter Giles, Stanford University, 1999). 

Other Interesting Articles

Web-View
Print Page
Open in new window
Estimated DIN-A4 page-width
Go to Editor View