E-Print Archive

There are 4354 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
Evolution of Magnetic Helicity in Solar Cycle 24 View all abstracts by submitter

Valery Pipin   Submitted: 2019-06-04 19:46

We propose a novel approach to reconstruct the surface magnetic helicity density on the Sun or Sun-like stars. The magnetic vector potential is determined via decomposition of vector magnetic-field measurements into toroidal and poloidal components. The method is verified using data from a non-axisymmetric dynamo model. We apply the method to vector field synoptic maps from the Helioseismic and Magnetic Imager on board the Solar Dynamics Observatory to study the evolution of the magnetic helicity density during solar cycle 24. It is found that the mean helicity density of the non-axisymmetric magnetic field of the Sun evolves in a way similar to that reported for the current helicity density of the solar active regions. It predominantly has a negative sign in the northern hemisphere, while it is mainly positive in the southern hemisphere. Also, the hemispheric helicity rule for the non-axisymmetric magnetic field showed the sign inversion at the end of cycle 24. The evolution of the magnetic helicity density of a large-scale axisymmetric magnetic field is different from what is predicted by dynamo theory. On one hand, the mean large- and small-scale components of magnetic helicity density display the hemispheric helicity rule of opposite signs at the beginning of cycle 24. However, later in the cycle, the two helicities exhibit the same sign, in contrast with theoretical expectations.

Authors: V.V. Pipin, A.A. Pevtsov, Yang Liu, A.G. Kosovichev
Projects: None

Publication Status: Published online in ApJL
Last Modified: 2019-06-05 14:16
Go to main E-Print page  Spectroscopy and Differential Emission Measure diagnostics  of a coronal dimming associated with a fast halo CME  Damping of Propagating Kink Waves in the Solar Corona  Edit Entry  Download Preprint  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
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)
Mixed properties of slow magnetoacoustic and entropy waves in a plasma with heating/cooling misbalance
The morphology of average solar flare time profiles from observations of the Sun's lower atmosphere
Indications of stellar coronal mass ejections through coronal dimmings
Could switchbacks originate in the lower solar atmosphere? II. Propagation of switchbacks in the solar corona
Solar large-scale magnetic field and cycle patterns in solar dynamo
Three-dimensional magnetic reconnection in astrophysical plasmas
Energy partition in a confined flare with an extreme-ultraviolet late phase
Alfvén wave heating in partially ionized thin threads of solar prominences
He I 10830 Dimming During Solar Flares, I: The Crucial Role of Non-Thermal Collisional Ionisations
Separating aa-index into Solar and Hale Cycle Related Components Using Principal Component Analysis
Inward Propagating Plasma Parcels in the Solar Corona: Models with Aerodynamic Drag, Ablation, and Snowplow Accretion
Energetics and 3-D Structure of Elementary Events in Solar Coronal Heating
Stellar Superflares Observed Simultaneously with Kepler and XMM-Newton
Medium-term predictions of F10.7 and F30 cm solar radio flux with the adaptive Kalman filter
Resonances in a Coronal Loop Driven by Torsional Alfvén Waves Propagating from the Photosphere
Effects of external flow on resonant absorption of coronal loop kink oscillations driven by an external fast wave: Selective excitation problem
Emerging Dimming as Coronal Heating Episodes
Proxy-Based Prediction of Solar Extreme Ultraviolet Emission using Deep Learning

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