Leptocline as a Shallow Substructure of Near-Surface Shear Layer in 3D Radiative Hydrodynamic Simulations

Abstract

Understanding effects driven by rotation in the solar convection zone is essential for many problems related to solar activity, such as the formation of differential rotation, meridional circulation, and others. We analyze realistic 3D radiative hydrodynamics simulations of solar subsurface dynamics in the presence of rotation in a local domain 80 Mm wide and 25 Mm deep, located at 30 degrees latitude. The simulation results reveal the development of a shallow 10-Mm deep substructure of the Near-Surface Shear Layer (NSSL), characterized by a strong radial rotational gradient and self-organized meridional flows. This shallow layer ("leptocline") is located in the hydrogen ionization zone associated with enhanced anisotropic overshooting-type flows into a less unstable layer between the H and HeII ionization zones. We discuss current observational evidence of the presence of the leptocline and show that the radial variations of the differential rotation and meridional flow profiles obtained from the simulations in this layer qualitatively agree with helioseismic observations.

11 pages, 8 figures, submitted to MNRAS

References in corpus (5)

• A Comprehensive Method to Measure Solar Meridional Circulation and Center-to-Limb Effect Using Time-Distance Helioseismology
• The radial gradient of the near-surface shear layer of the Sun
• Changes in the near-surface shear layer of the Sun
• Evolution of Subsurface Zonal and Meridional Flows in Solar Cycle 24 from Helioseismological Data
• Reconstruction of Solar Subsurfaces by Local Helioseismology

Cited by in corpus (4)

• Non-zero phase-shifts of acoustic waves in the lower solar atmosphere measured from realistic simulations and their role in local helioseismology
• Exploring the Temporal Variation of the Solar Quadrupole Moment J2
• Rotational radial shear in the low solar photosphere. Direct detection from high-resolution spectro-imaging
• Activity-Cycle Variations of Convection Scales in Subsurface Layers of the Sun