Rotation suppresses giant-scale solar convection.

Area of Science:

• Solar Physics
• Plasma Physics
• Fluid Dynamics

Background:

• The absence of giant convection cells near the Sun's surface is a major puzzle in solar modeling.
• Understanding solar convection is crucial for explaining the Sun's energy transport and surface phenomena.

Purpose of the Study:

• To explain the observational absence of giant convection cells near the Sun's surface.
• To investigate the influence of rotation on solar convection dynamics and length scales.

Main Methods:

• Developing a theoretical model incorporating Coriolis forces, vortex stretching, baroclinic torques, and nonlinear advection.
• Deriving estimates for dominant convection length scales and dynamical amplitudes based on fundamental physical quantities.
• Analyzing the dynamical Rossby number to assess the impact of rotation on convection.

Main Results:

• Rotation significantly suppresses convective velocities and enhances thermal transport efficiency.
• A characteristic convection length scale of approximately 30 Mm is predicted, explaining the lack of larger-scale flows.
• The model predicts weak flow amplitudes at scales of 100-200 Mm, consistent with observations.

Conclusions:

• Rotation is the primary driver for the suppressed convection and smaller length scales observed in the Sun.
• The proposed model successfully explains the conundrum of absent giant convection cells by incorporating rotational effects.
• The findings suggest a dynamically constrained convection zone where rotation limits the scale of convective motions.