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
Resolving the Azimuthal Ambiguity in Vector Magnetogram Data with the Divergence-Free Condition: the Effects of Noise and Limited Spatial Resolution View all abstracts by submitter

Ashley Crouch   Submitted: 2012-10-15 17:56

We investigate how the azimuthal ambiguity in solar vector magnetogram data can be resolved by using the divergence-free property of magnetic fields. In a previous article, by Crouch, Barnes, and Leka (Solar Phys. 260, 271, 2009), error-free synthetic data were used to test several methods that each make a different assumption about how the divergence-free property can be used to resolve the ambiguity. In this paper this testing is continued with an examination of the effects of Poisson photon noise and limited instrumental spatial resolution. We find that all currently available methods based on the divergence-free property can produce undesirable results when photon noise or unresolved structure are present in the data. We perform a series of experiments aimed at improving the performance of the global minimisation method, which is the most promising of the methods. We present a two-step approach that produces reasonable results in tests using synthetic data. The first step of this approach involves the global minimisation of a combination of the absolute value of the approximation for the divergence and a smoothness constraint, which is designed to minimise the difference between the magnetic field in neighbouring pixels. In the second step, pixels with measurements known to be strongly affected by photon noise are revisited with a smoothing algorithm that also seeks to minimise the difference between the magnetic field in neighbouring pixels.

Authors: Ashley D. Crouch
Projects: None

Publication Status: Accepted for publication in Solar Physics
Last Modified: 2012-10-19 09:58
Go to main E-Print page  On the Relationship Between Coronal Magnetic Decay Index and CME Speed  Least-Squares Fitting Methods for Estimating the Winding Rate in Twisted Magnetic-Flux Tubes  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