# Solar overshoot region and small-scale dynamo with realistic energy flux

## TL;DR

This study uses high-resolution simulations with realistic solar parameters to explore the overshoot region and small-scale dynamo, revealing a steep transition at the convection zone base and enhanced dynamo efficiency with lower energy flux.

## Contribution

First high-resolution simulation of the solar overshoot region with realistic energy flux, demonstrating a steep transition and increased dynamo efficiency.

## Key findings

- Steep transition from convection to radiative zone at 0.4% of pressure scale height.
- Subadiabatic bottom of convection zone suppresses downflows.
- Small-scale dynamo efficiency increases with smaller energy flux.

## Abstract

We carry out high resolution calculations of the solar overshoot region with unprecedentedly realistic parameters, especially the small energy flux compared with $\rho c^3_\mathrm{s}$, where $\rho$ and $c_\mathrm{s}$ are density and speed of sound. Our main purpose is to investigate behavior of the overshoot and the small-scale dynamo with parameters as close as possible to those of the Sun. Our calculations show that the bottom part of the convection zone becomes subadiabatic, which efficiently suppresses downflows. As a result we see a steep transition from the CZ to the RZ whose width is estimated 0.4% of the local pressure scale height. This result is consistent with a semi-analytic convection/overshoot model. We also find that the small-scale dynamo becomes efficient with a smaller energy flux. The sudden suppression of the downflows around the base of the convection zone increases the efficiency of the small-scale dynamo.