National Aeronautics and Space Administration

Living With A Star

Targeted Research and Technology

Determination of the large-scale and meridional flows in the deep convection zone by time-distance helioseismology

ROSES ID: NNH08ZDA001N      Selection Year: 2009      

Program Element: Focused Science Topic

Principal Investigator: Alexander Kosovichev

Affiliation(s): Stanford University

Project Member(s):
Scherrer, Philip H. Co-I/Institutional PI HEPL
Zhao, Junwei Collaborator null
Hartlep, Thomas Collaborator NASA Ames Research Center
Parchevsky, Konstantin Collaborator Stanford University
Mansour, Nagi Nicolas Consultant NASA Ames Research Center


We propose a focused investigation with the main goal of

detecting the return meridional flow and measuring the

properties of deep large-scale flows associated with formation

of active regions. Determination of the large-scale and

meridional flows in the solar convection zone is crucial for

understanding and modeling the solar dynamo and making sort-

and long-term predictions of solar activity. There is no doubt

that the large-scale and meridional flows play a significant

role in the dynamo operation and in the generation of active

regions. The local helioseismology inferences have revealed a

complicated dynamics associated with the meridional flux

transport and evolution of active regions in the upper

convection zone. It has been shown that these inferences have a

profound effect on the flux-transport mechanism. However, the

effects of these flows on the properties of the solar dynamo

and active region formation are far from understanding. For

this it is particularly important to determine the structure

and dynamics of these flows in the deep convection zone

including the tachocline where the solar magnetic fields are

believed to be generated and organized. This problem is

difficult because the deep flows are relatively weak, and their

helioseismic signals are difficult to extract from the noisy

oscillation data contaminated by the surface magnetism effects.

For tuning of the helioseismic measurements and verification

and testing of the results we propose to use numerical

simulations of stochastically excited acoustic waves in 3D MHD

models of the whole Sun, and use the simulation data for

developing, the helioseismic techniques. This work includes a

thorough investigation of systematic errors and uncertainties,

including potential contamination by the surface magnetism



Performance YearReferenceInvestigation TypeActions
1Pipin, V. V.; Kosovichev, A. G.; (2011), Mean-field Sol...
not set


Performance YearReferenceActions
1Kosovichev, A.; Zhao, J.; Sekii, T.; Nagashima, K.; ...
1Nagashima, K.; Zhao, J.; Kosovichev, A. G.; Sekii, T...
1Hartlep, Thomas; Roth, M.; Doerr, H.; Zhao, J.; Koso...

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