COFFIES Community Workshop - NSSL

COFFIES Theme Workshop on the Near-Surface Shear Layer (NSSL)

The COFFIES DRIVE Science Center is pleased to announce our first science-theme oriented virtual workshops on the first three Fridays of October. We aim to understand the solar cycle as the Consequence of Fields and Flows in the Interior and Exterior of the Sun (COFFIES). We welcome community participation in the discussions of science related to the Near-Surface Shear Layer (NSSL), the Tachocline, and Flux Transport & Emergence (FT&E). Zoom meetings will begin at 9 am PT on October 7, 14, and 21. Each session will review current understanding and provide time for brief contributed presentations.

The upper solar convection zone possesses a boundary layer of radial rotational shear known as the near-surface shear layer. Unlike the tachocline, the NSSL can be observed in detail by helioseismic techniques, and yet outstanding questions persist concerning its origins and its potential role in the dynamo process. The goal of this meeting is to review recent observational and theoretical progress in understanding the formation of the solar NSSL.

We encourage participants to actively contribute to these discussions by submitting short (2–3 slide) presentations to help spur discussion and, ultimately, future studies.

Please send contributions to the NSSL Theme Baristas: Nick Featherstone and Rudi Komm.

COFFIES Community Workshop - NSSL
COFFIES Community Workshop - NSSL
Time (PT) Topic
Opening Remarks
09:10 Science Introduction
Near Surface Shear Layer
Nick Featherstone (SWRI)
09:30 Invited Talk
Radial Gradient of the Rotation Rate Measured in the NSSL
Rudi Komm (NSO)
10:00 Discussion
Temporal variations (solar cycle) in the NSSL: rotation, meridional and the cross-equator flows and their relationships to surface magnetic field
10:30 Invited Talk
Leptocline as a Substructure of Near-Surface Shear Layer of the Sun
Irina Kitiashvili (NASA Ames)
11:00 Discussion
Progress in observations and available data sets e.g. PHI on board Solar Orbiter
11:30 Discussion
Spatial scales and time variation of solar subsurface convection
12:00 BREAK
13:00 Invited Talk
Exploring the MRI in the solar Near-surface Shear Layer
Kyle Augustson (Northwestern University)
13:30 Discussion
Measurements and models of solar interior convection
14:00 Invited Talk
Simultaneous reproduction of fast equator, near-surface shear layer, and poleward meridional flow in high-resolution numerical simulation.
Hideyuki Hotta (Chiba University)
14:30 Discussion
Why don't global models reproduce near-surface shear?
15:00 Discussion
An explanation of the NSSL based on thermal wind balance
15:30 Discussion
Open Discussion
16:00 BREAK
The NSSL Theme Baristas would like to thank the invited speakers, as well as all the workshop attendees for their participation. Particularly, thanks to the following people for contributing suggested discussion topics:
  • Paul Rajaguru
  • Aneta Wisniewska
  • Sasha Kosovichev
  • Vincent Boening
  • Loren Matilsky
  • Bibhuti Kumar Jha