Events

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
Agenda

Time (PT)	Topic
09:00	OVERVIEW 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 Lunch
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 Adjourn