E-Print Archive

There are 3989 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
Center-to-Limb Variability of Hot Coronal EUV Emissions During Solar Flares View all abstracts by submitter

Edward Thiemann   Submitted: 2018-01-08 09:48

It is generally accepted that densities of quiet sun and active region plasma are sufficiently low to justify the optically thin approximation, and it is commonly used in the analysis of line emissions from plasma in the solar corona. However, densities of solar flare loops are substantially higher, compromising the optically thin approximation. This study begins with a radiative transfer model that uses typical solar flare densities and geometries to show that hot coronal emission lines are not generally optically thin. Further, the model demonstrates that the observed line intensity should exhibit center-to-limb variability (CTLV), with flares observed near the limb being dimmer than those occurring near disk-center. The model predictions are validated with an analysis of over 200 flares observed by EVE on SDO that uses 6 lines, with peak formation temperatures between 8.9 and 15.8 MK, to show limb flares are systematically dimmer than disk-center flares. The data are then used to show that the electron column density along the line-of-sight typically increases by 1.76 x 1019cm-2 for limb flares over the disk-center flare value. It is shown that CTLV of hot coronal emissions reduces the amount of ionizing radiation propagating into the solar system, and changes the relative intensities of lines and bands commonly used for spectral analysis.

Authors: Edward Thiemann, Phillip Chamberlin, Francis Eparvier, Luke Epp
Projects: SDO-EVE

Publication Status: Accepted by Solar Physics
Last Modified: 2018-01-09 11:30
Go to main E-Print page  Three-dimensional Forward-fit Modeling of the Hard X-Ray and Microwave Emissions of the 2015 June 22 M6.5 Flare  A time dependent relation between EUV solar flare light-curves from lines with differing formation temperatures  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
Dynamo Wave Patterns Inside the Sun Revealed by Torsional Oscillations
Evidence of Twisting and Mixed-polarity Solar Photospheric Magnetic Field in Large Penumbral Jets: IRIS and Hinode Observations
Dissipation scale lengths of density turbulence in the inner solar wind
On the Possibility of Generating Harmonics of the Electron Plasma Frequency in the Solar Atmosphere due to Explosive Instability in a System of Interpenetrating Electron and Ion Flows
Determination of the total accelerated electron rate and power using solar flare hard X-ray spectra
Transition from axi- to nonaxisymmetric dynamo modes in spherical convection models of solar-like stars
Can high-mode magnetohydrodynamic waves propagating in a spinning macrospicule be unstable due to the Kelvin-Helmholtz instability?
The development of lower-atmosphere turbulence early in a solar flare
Determining the parameter for the linear force-free magnetic field model with multi-dipolar configurations using deep neural networks
No unique solution to the seismological problem of standing kink MHD waves
Untwisting and Disintegration of a Solar Filament Associated with Photospheric Flux Cancellation
Modeling of the sunspot-associated microwave emission using a new method of DEM inversion
Energy transport and heating by torsional Alfvén waves propagating from the photosphere to the corona in the quiet Sun
A Two-Step Magnetic Reconnection in a Confined X-class Flare in Solar Active Region 12673
Lifetimes and Emergence/Decay Rates of Star Spots on Solar-type Stars Estimated by Kepler Data in Comparison with Those of Sunspots
IRIS and SDO Observations of Solar Jetlets Resulting from Network-edge Flux Cancelation
Si IV Resonance Line Emission During Solar Flares: Non-LTE, Non-equilibrium, Radiation Transfer Simulations
Study of current sheets in the wake of two crossing filaments eruption
Quasi-periodic fast propagating magnetoacoustic waves during the magnetic reconnection between solar coronal loops
Spectroscopic EUV observations of impulsive solar energetic particle event sources

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