Solar cycle observations

A Norton, R Howe, L Upton, I Usoskin - Space Science Reviews, 2023 - Springer
We describe the defining observations of the solar cycle that provide constraints for the
dynamo processes operating within the Sun. Specifically, we report on the following topics …

Theory of solar oscillations in the inertial frequency range: Amplitudes of equatorial modes from a nonlinear rotating convection simulation

Y Bekki, RH Cameron, L Gizon - Astronomy & Astrophysics, 2022 - aanda.org
Context. Several types of inertial modes have been detected on the Sun. Properties of these
inertial modes have been studied in the linear regime, but have not been studied in …

Theory of solar oscillations in the inertial frequency range: Linear modes of the convection zone

Y Bekki, RH Cameron, L Gizon - Astronomy & Astrophysics, 2022 - aanda.org
Context. Several types of global-scale inertial modes of oscillation have been observed on
the Sun. These include the equatorial Rossby modes, critical-latitude modes, and high …

The Sun's differential rotation is controlled by high-latitude baroclinically unstable inertial modes

Y Bekki, RH Cameron, L Gizon - Science Advances, 2024 - science.org
Rapidly rotating fluids have a rotation profile that depends only on the distance from the
rotation axis, in accordance with the Taylor-Proudman theorem. Although the Sun was …

Three-dimensional non-kinematic simulation of the post-emergence evolution of bipolar magnetic regions and the Babcock-Leighton dynamo of the Sun

Y Bekki, RH Cameron - Astronomy & Astrophysics, 2023 - aanda.org
Context. The Babcock-Leighton flux-transport model is a widely accepted dynamo model of
the Sun that can explain many observational aspects of solar magnetic activity. This dynamo …

The meridional circulation of the Sun: Observations, theory and connections with the solar dynamo

AR Choudhuri - Science China Physics, Mechanics & Astronomy, 2021 - Springer
The meridional circulation of the Sun, which is observed to be poleward at the surface,
should have a return flow at some depth. Since large-scale flows like the differential rotation …

Solar meridional circulation from twenty-one years of SOHO/MDI and SDO/HMI observations-Helioseismic travel times and forward modeling in the ray approximation

ZC Liang, L Gizon, AC Birch, TL Duvall… - Astronomy & …, 2018 - aanda.org
Context. The solar meridional flow is an essential ingredient in flux-transport dynamo
models. However, no consensus on its subsurface structure has been reached. Aims. We …

Convective velocity suppression via the enhancement of the subadiabatic layer: role of the effective Prandtl number

Y Bekki, H Hotta, T Yokoyama - The Astrophysical Journal, 2017 - iopscience.iop.org
It has recently been recognized that the convective velocities achieved in current solar
convection simulations might be overestimated. The newly revealed effects of the prevailing …

Forward modeling helioseismic signatures of one-and two-cell meridional circulation

AM Stejko, AG Kosovichev, VV Pipin - The Astrophysical Journal, 2021 - iopscience.iop.org
Using a 3D global solver of the linearized Euler equations, we model acoustic oscillations
over background velocity flow fields of single-cell meridional circulation with deep and …

Magnetic and rotational quenching of the Λ effect

PJ Käpylä - Astronomy & Astrophysics, 2019 - aanda.org
Context. Differential rotation in stars is driven by the turbulent transport of angular
momentum. Aims. Our aim is to measure and parameterize the non-diffusive contribution to …