E-Print Archive

There are 4524 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
Structure of the transition region and the low corona from TRACE and SDO observations near the limb View all abstracts by submitter

Costas Alissandrakis   Submitted: 2019-07-21 00:57

We examined the structure near the solar limb in TRACE images of the continuum and in the 1600 and 171 Å bands as well as in SDO images in the continuum (from HMI) and all AIA bands. The images in different wavelength bands were carefully coaligned by using the position of Mercury for TRACE and Venus for SDO during their transit in front of the solar disk in 1999 and 2012 respectively. Chromospheric absorbing structures in the TRACE 171 Å band are best visible 7" above the white light limb, very close to the inner limb, defined as the inflection point of the rising part of the center-to-limb intensity variation. They are correlated with, but are not identical to spicules in emission, seen in the 1600 Å band. Similar results were obtained from AIA and SOT images. Tall spicules in 304 Å are not associated with any absorption in the higher temperature bands. Performing azimuthal averaging of the intensity over 15 degree sectors near the N, S, E and W limbs, we measured the height of the limb and of the peak intensity in all AIA bands. We found that the inner limb height in the transition region AIA bands increases with wavelength, consistent with a bound-free origin of the absorption from neutral H and He. From that we computed the column density and the density of neutral hydrogen as a function of height. We estimated a height of (2300 ? 500)km for the base of the transition region. Finally, we measured the scale height of the AIA emission of the corona and associated it with the temperature; we deduced a value of (1.24 ? 0.25) 10 6 K for the polar corona.

Authors: C. E. Alissandrakis, A. Valentino
Projects: SDO-AIA

Publication Status: In press, Solar Physics
Last Modified: 2019-07-21 23:47
Go to main E-Print page  Coronal Loop Scaling Laws for Various Forms of Parallel Heat Conduction   Quantifying the relationship between Moreton-Ramsey waves and   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
Coronal seismology by slow waves in non-adiabatic conditions
Exploring the Ideal MHD Quasi-Modes of a Plasma Interface with a Thick Nonuniform Transition
Changes of Magnetic Energy and Helicity in Solar Active Regions from Major Flares
Spectroscopic and Imaging Observations of Spatially Extended Magnetic Reconnection in the Splitting of a Solar Filament Structure
The Universality of Power Law Slopes in the Solar Photosphere and Transition Region Observed with HMI and IRIS
Turbulence and Anomalous Resistivity inside Near-Earth Magnetic Clouds
On the specific energy and pressure in near-Earth magnetic clouds
Solar Energetic Particle Event Associated with the 2012 July 23 Extreme Solar Storm
Investigation of Energetic Particle Release Using Multi-point Imaging and In Situ Observations
Shock Properties and Associated Characteristics of Solar Energetic Particles in the 2017 September 10 GLE event
Dimensionality of Solar Magnetic Reconnection
Microwave Perspective on Magnetic Breakout Eruption
Effects of Coronal Density and Magnetic Field Distributions on a Global Solar EUV Wave
Multi-spacecraft Observations of the Coronal and Interplanetary Evolution of a Solar Eruption Associated with Two Active Regions
Sun-to-Earth Characteristics of the 2012 July 12 Coronal Mass Ejection and Associated Geo-effectiveness
The effect of nanoflare flows on EUV spectral lines
On some features of the solar proton event on 2021 October 28 GLE73
The role and contribution of magnetic fields, characterized via their magnetic flux, to the statistical structuring of the solar atmosphere
Do periods of decayless kink oscillations of solar coronal loops depend on noise?
Automatic detection technique for solar filament oscillations in GONG data

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