Speaker
Description
First Name: Matthias
Last Name: Rempel
Email Address: rempel@ucar.edu
Affiliation: High Altitude Observatory, NSF National Center for Atmospheric Research
All Authors: Matthias Rempel
Abstract: The Sun is a unique star in the sense that we can observe it at high resolution and study phenomena at a detail that is hidden in stellar observations. This applies specifically to small-scale magnetic fields that are organized on the stellar surface on scale of granulation and smaller. Observations have shown that these small-scale magnetic fields are ubiquitous in the solar atmosphere and appear to be mostly independent of the solar sunspot cycle, which provides strong support for a small-scale magnetic dynamo. In this talk I will provide an overview of developments over the past 10-20 years. Recent research has clarified the role of the magnetic Prandtl number for small-scale dynamo action during both kinematic and saturated phase of dynamo operation and demonstrated that the low Pm found in stellar convection zones does not prevent small-scale dynamo operation as thought earlier. Simulations of strongly stratified convection point to a small-scale dynamo that operates over a wide range of scales in the solar convection zone and produces a magnetic field of a large enough strength to have a dynamical impact on convection. I discuss implications for the convection zone as well as heating of the solar atmosphere.