E-Print Archive

There are 4371 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
f-mode strengthening from a localized bipolar subsurface magnetic field View all abstracts by submitter

Axel Brandenburg   Submitted: 2020-05-23 01:40

Recent numerical work in helioseismology has shown that a periodically varying subsurface magnetic field leads to a fanning of the f-mode, which emerges from the density jump at the surface. In an attempt to model a more realistic situation, we now modulate this periodic variation with an envelope, giving thus more emphasis on localized bipolar magnetic structures in the middle of the domain. Some notable findings are: (i) compared to the purely hydrodynamic case, the strength of the f-mode is significantly larger at high horizontal wavenumbers k, but the fanning is weaker for the localized subsurface magnetic field concentrations investigated here than the periodic ones studied earlier; (ii) when the strength of the magnetic field is enhanced at a fixed depth below the surface, the fanning of the f-mode in the kω diagram increases proportionally in such a way that the normalized f-mode strengths remain nearly the same in different such cases; (iii) the unstable Bloch modes reported previously in case of harmonically varying magnetic fields are now completely absent when more realistic localized magnetic field concentrations are imposed beneath the surface, thus suggesting that the Bloch modes are unlikely to be supported during most phases of the solar cycle; (iv) the f-mode strength appears to depend also on the depth of magnetic field concentrations such that it shows a relative decrement when the maximum of the magnetic field is moved to a deeper layer. We argue that detections of f-mode perturbations such as those being explored here could be effective tracers of solar magnetic fields below the photosphere before these are directly detectable as visible manifestations in terms of active regions or sunspots.

Authors: Authors:Nishant K. Singh, Harsha Raichur, Maarit J. Käpylä, Matthias Rheinhardt, Axel Brandenburg, Petri J. Käpylä
Projects: None

Publication Status: Geophys. Astro. Fluid 2020, 114, 196-212 (2020)
Last Modified: 2020-05-27 13:13
Go to main E-Print page  Sunquake with a second-bounce, other sunquakes and emission associated with X9.3 flare of 6 September 2017.  II. Proposed interpretation  Imaging and spectral study on the null point of a fan-spine structure during a solar flare  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
The Poissonian origin of power laws in solar flare waiting time distributions
Correlation of the sunspot number and the waiting time distribution of solar flares, coronal mass ejections, and solar wind switchback events observed with the Parker Solar Probe
Self-organized criticality in stellar flares
Finite system-size effectrs in self-organizing criticality systems
Global energetics of solar flares. XII. Energy scaling laws
Global energetics of solar flares. XI. Flare magnitude predictions of the GOES class
Are the Magnetic Fields Radial in the Solar Polar Region?
Fast magnetoacoustic wave trains: from tadpoles to boomerangs
Multi-channel coronal hole detection with convolutional neural networks
FOXSI-2 Solar Microflares. II. Hard X-ray Imaging Spectroscopy and Flare Energetics
Structure and Evolution of an Inter–Active Region Large-scale Magnetic Flux Rope
Variation of Magnetic Flux Ropes through Major Solar Flares
MHD Modeling of Solar Coronal Magnetic Evolution Driven by Photospheric Flow
The Causes of Peripheral Coronal Loop Contraction and Disappearance Revealed in a Magnetohydrodynamic Simulation of Solar Eruption
The Sun's Dynamic Extended Corona Observed in Extreme Ultraviolet
Magnetohydrodynamic Simulations of Spicular Jet Propagation Applied to Lower Solar Atmosphere Model
Thermal Trigger for Solar Flares II: Effect of the Guide Magnetic Field
The role of non-axisymmetry of magnetic flux rope in constraining solar eruptions
Energy budget of plasma motions, heating, and electron acceleration in a three-loop solar flare
Space weather: the solar perspective - an update to Schwenn (2006)

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