E-Print Archive

There are 3950 abstracts currently viewable.


Advanced Search
Main Page Add New E-Print Submitter
News Help/FAQ About Preferences
Manage Key Phrase
The density compression ratio of shock fronts associated with coronal mass ejections View all abstracts by submitter

Ryun Young Kwon   Submitted: 2018-01-16 11:51

We present a new method to extract the three-dimensional electron density profile and density compression ratio of shock fronts associated with Coronal Mass Ejections (CMEs) observed in white light coronagraph images. We demonstrate the method with two examples of fast halo CMEs (∼ 2000 km s-1) observed on 2011 March 7 and 2014 February 25. Our method uses the ellipsoid model to derive the three-dimensional (3D) geometry and kinematics of the fronts. The density profiles of the sheaths are modeled with double-Gaussian functions with four free parameters and the electrons are distributed within thin shells behind the front. The modeled densities are integrated along the lines of sight to be compared with the observed brightness in COR2-A, and a χ2 approach is used to obtain the optimal parameters for the Gaussian profiles. The upstream densities are obtained from both the inversion of the brightness in a pre-event image and an empirical model. Then the density ratio and Alfvénic Mach number are derived. We find that the density compression peaks around the CME nose, and decreases at larger position angles. The behavior is consistent with a driven shock at the nose and a freely-propagating shock wave at the CME flanks. Interestingly, we find that the supercritical region extends over a large area of the shock and last longer (several tens of minutes) than past reports. It follows that CME shocks are capable of accelerating energetic particles in the corona over extended spatial and temporal scales and are likely responsible for the wide longitudinal distribution of these particles in the inner heliosphere. Our results also demonstrate the power of multi-viewpoint coronagraphic observations and forward modeling in remotely deriving key shock properties in an otherwise inaccessible regime.

Authors: Ryun-Young Kwon, Angelos Vourlidas
Projects: None

Publication Status: Accepted for publication in the Journal of Space Weather and Space Climate
Last Modified: 2018-01-17 12:45
Go to main E-Print page  Sun-to-Earth MHD Simulation of the 14 July 2000    Evolution of Photospheric Flow and Magnetic Fields Associated with The   2015 June 22 M6.5 Flare  Edit Entry  Download Preprint  Delete Entry 

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
Frequency rising sub-THz emission from solar flare ribbons
Particle acceleration in coalescent and squashed magnetic islands I. Test particle approach
Statistical Analysis of Torus and Kink Instabilities in Solar Eruptions
Solar Eruptions, Forbush Decreases and Geomagnetic Disturbances from Outstanding Active Region 12673
Coronal hard X-ray sources revisited
Manifestations of bright points observed in G-band and Ca II H by Hinode/SOT
Propagation of Leaky MHD Waves at Discontinuities with Tilted Magnetic Field
Time variations of the non-potential and volume-threading magnetic helicities
Advances in mean-field dynamo theory and applications to astrophysical turbulence
Reverse Current Model for Coronal Mass Ejection Cavity Formation
Predictions of DKIST/DL-NIRSP Observations for an Off-limb Kink-unstable Coronal Loop
Exploring the biases of a new method based on minimum variance for interplanetary magnetic clouds
The non-modal onset of the tearing instability
SpatioTemporal Evolution and North-South Asymmetry of Quasi-Biennial Oscillations in the Coronal Fe XIV Emission
Corotating Shock Waves and the Solar-Wind Source of Energetic Ion Abundances: Power Laws in A/Q
Coronal condensations caused by magnetic reconnection between solar coronal loops
Measurement of Vector Magnetic Field in a Flare kernel with a Spectropolarimetric Observation in He I 10830 A
The Relation Between Escape and Scattering Times of Energetic Particles in a Turbulent Magnetized Plasma: Application to Solar Flares
Implications of loop-top origin for microwave, hard X-ray, and low-energy gamma-ray emissions from behind the limb flares
Solar radio emission as a disturbance of aeronautical radionavigation

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