E-Print Archive

There are 4499 abstracts currently viewable.


Search:

Advanced Search
Options
Main Page Add New E-Print Submitter
Information
Feedback
News Help/FAQ About Preferences
Manage Key Phrase
Notification
Transition from axi- to nonaxisymmetric dynamo modes in spherical convection models of solar-like stars View all abstracts by submitter

Axel Brandenburg   Submitted: 2018-12-26 02:55

We seek to understand the transition from nearly axisymmetric configurations at solar rotation rates to nonaxisymmetric configurations for rapid rotation using 3D numerical simulations of turbulent convection and considering rotation rates between 1 and 30 times the solar value. We find a transition from axi- to nonaxisymmetric solutions at around 1.8 times the solar rotation rate. This transition coincides with a change in the rotation profile from antisolar- to solar-like differential rotation with a faster equator and slow poles. In the solar-like rotation regime, the field configuration consists of an axisymmetric oscillatory field accompanied by an m=1 azimuthal mode (two active longitudes), which also shows temporal variability. At slow (rapid) rotation, the axisymmetric (nonaxisymmetric) mode dominates. The axisymmetric mode produces latitudinal dynamo waves with polarity reversals, while the nonaxisymmetric mode often exhibits a drift in the rotating reference frame and the strength of the active longitudes changes cyclically over time between the different hemispheres. Most of the obtained dynamo solutions exhibit cyclic variability either caused by latitudinal or azimuthal dynamo waves. In an activity-period diagram, the cycle lengths normalized by the rotation period form two different populations as a function of rotation rate or magnetic activity level. The slowly rotating axisymmetric population lies close to what is called the inactive branch in observations, while the rapidly rotating models are close to the superactive branch with a declining cycle to rotation frequency ratio with increasing rotation rate. We can successfully reproduce the transition from axi- to nonaxisymmetric dynamo solutions for high rotation rates, but high-resolution simulations are required to limit the effect of rotational quenching of convection at rotation rates above 20 times the solar value.

Authors: Viviani, M., Warnecke, J., Käpylä, M. J., Käpylä, P. J., Olspert, N., Cole-Kodikara, E. M., Lehtinen, J. J., & Brandenburg, A.
Projects: None

Publication Status: A&A 616, A160 (2018)
Last Modified: 2018-12-26 12:06
Go to main E-Print page  Determination of the total accelerated electron rate and power using solar flare hard X-ray spectra  Can high-mode magnetohydrodynamic waves propagating in a spinning macrospicule be unstable due to the Kelvin--Helmholtz instability?  Edit Entry  Download Preprint  Submitter's Homepage Delete Entry 

Key
Go to main E-Print pageGo to main E-Print page.
Previous AbstractPrevious Abstract.
Next AbstractNext Abstract.
Download PreprintDownload Preprint.
Submitter's HomepageSubmitters Homepage.
Edit EntryEdit Entry.
View All Abstracts By SubmitterView all abstracts by submitter.
Delete AbstractDelete abstract.

Latest Entries
Small-scale solar jet formation and their associated waves and instabilities
Invited Review: Short-term Variability with the Observations from the Helioseismic and Magnetic Imager (HMI) Onboard the Solar Dynamics Observatory (SDO): Insights into Flare Magnetism
A first look at the submillimeter Sun with ALMA
Data-driven modeling of solar coronal magnetic field evolution and eruptions
Properties and Energetics of Magnetic Reconnection: I. Evolution of Flare Ribbons
A new look at the frequency-dependent damping of slow-mode waves in the solar corona
What determines active region coronal plasma composition?
Characteristics and evolution of sheath and leading edge structures of interplanetary coronal mass ejections in the inner heliosphere based on Helios and Parker Solar Probe observations
Slow magnetoacoustic oscillations in stellar coronal loops
Kink Oscillation of a Flux Rope During a Failed Solar Eruption
A publicly available multi-observatory data set of an enhanced network patch from the Photosphere
Type IV Radio Bursts and Associated Active Regions in the Sunspot Cycle 24
Theory of Fluid Instabilities in Partially Ionized Plasmas: An Overview
Quasiperiodic Energy Release and Jets at the Base of Solar Coronal Plumes
The Coupling of an EUV Coronal Wave and Ion Acceleration in a Fermi-LAT Behind-the-Limb Solar Flare
Reconciling Power Law Slopes in Solar Flare and Nanoflare Size Distributions
A Model of Homologous Confined and Ejective Eruptions Involving Kink Instability and Flux Cancellation
Detection of stellar-like abundance anomalies in the slow solar wind
Magnetosheath jet occurrence rate in relation to CMEs and SIRs
Microwave Perspective on Magnetic Breakout Eruption

Related Pages
MSU Solar Physics.
Max Millennium Science Mail Archive.
Max Millennium Message of the Day Mail Archive.
Max Millennium Flare Catalog

Archive Maintainer
Alisdair Davey



© 2000-2020 Solar Physics Group - Montana State University