E-Print Archive

There are 4080 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
Densities Probed by Coronal Type III Radio Burst Imaging View all abstracts by submitter

Patrick McCauley   Submitted: 2018-08-15 18:46

We present coronal density profiles derived from low-frequency (80-240 MHz) imaging of three type III solar radio bursts observed at the limb by the Murchison Widefield Array (MWA). Each event is associated with a white light streamer at larger heights and is plausibly associated with thin extreme ultraviolet rays at lower heights. Assuming harmonic plasma emission, we find average electron densities of 1.8 x108 cm-3 down to 0.20 x108 cm-3 at heights of 1.3 to 1.9 solar radii. These values represent roughly 2.4-5.4x enhancements over canonical background levels and are comparable to the highest streamer densities obtained from data at other wavelengths. Assuming fundamental emission instead would increase the densities by a factor of 4. High densities inferred from type III source heights can be explained by assuming that the exciting electron beams travel along overdense fibers or by radio propagation effects that may cause a source to appear at a larger height than the true emission site. We review the arguments for both scenarios in light of recent results. We compare the extent of the quiescent corona to model predictions to estimate the impact of propagation effects, which we conclude can only partially explain the apparent density enhancements. Finally, we use the time- and frequency-varying source positions to estimate electron beam speeds of between 0.24 and 0.60 c.

Authors: Patrick I. McCauley, Iver H. Cairns, John Morgan
Projects: Murchison Widefield Array (MWA)

Publication Status: Accepted by Solar Physics
Last Modified: 2018-08-27 11:29
Go to main E-Print page  Diagnostic Analysis of the Solar Proton Flares of September 2017 by Their Radio Bursts  The Minimum Energy Principle Applied to Parker's Coronal Braiding and Nanoflaring Scenario  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
Magnetic Helicity from Multipolar Regions on the Solar Surface
The width distribution of solar coronal loops and strands - Are we hitting rock bottom ?
Exoplanet predictions based on harmonic orbit resonances
Order out of randomness: Self-organization processes in astrophysics
Convection-driven generation of ubiquitous coronal waves
The minimum energy principle applied to Parker's coronal braiding and nanoflaring scenario
Self-organizing systems in planetary physics: Harmonic resonances of planet and moon orbits
Global energetics of solar flares: VIII. The Low-Energy Cutoff
Global Energetics of Solar Flares: VII. Aerodynamic Drag in Coronal Mass Ejections
Self-organized criticality in solar and stellar flares: Are extreme events scale-free ?
A Wavelet Based Approach to Solar-Terrestrial Coupling
Interplanetary Type IV Bursts
High resolution observations with Artemis-IV and the NRH. I. Type IV associated narrow-band bursts
Detection of spike-like structures near the front of type-II burstsA
High resolution observations with Artemis-JLS, (II) Type IV associated intermediate drift bursts
Oscillation of a small Hα surge in a solar polar coronal hole
Radio Observations of the January 20, 2005 X-Class Event
Fine Structure of Metric Type-IV Radio Bursts Observed with the ARTEMIS-IV Radio Spectrograph: Association with Flares and Coronal Mass Ejections
Spectral Analysis of the September 2017 Solar Energetic Particle Events
Solar Energetic Particle Events Observed by the PAMELA Mission

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



© 2003 Solar Physics Group - Montana State University