The solar interface from the photosphere to the chromosphere and corona : contribution of eclipses and EUV filtergrams
type: Dataset
description: The solar interface region from the photosphere to the chromosphere and beyond to the lower corona has been best studied for a long time on the basis of flash spectra obtained during solar total eclipses. Eclipses are very favourable for this type of observation as the occultation takes place outside the Earth atmosphere and are therefore free of parasitic scattered light coming from the "occulting disk" (i.e., the Moon) a property of paramount importance when observing near the solar limb. The resolution of past flash spectra did not allow resolving the low layers of the transition region and were further hampered by non-linear effects affecting photographic films. Independently, EUV filtergrams of the limb region obtained in space were analyzed using one dimensional hydrostatic models like the VAL models but this method ignores the ubiquitous magnetic field emergence phenomenon associated with the chromospheric network and responsible for: i) spicules and interspicular regions, ii) coronal jets and macrospicules, and iii) the chromospheric prolateness. The components of the solar interface region are dynamical and different type of waves and magnetic reconnections are suggested to be at work. A jump of temperature from 0.01 to 1 MK is observed near the 2 Mm heights and higher, further producing a permanent solar wind flow. The heating processes responsible for this temperature jump and for the flow are not yet fully understood. In this thesis, we reconsider these problems on the basis of original, superior flash spectra which benefit from present technology such as CCD detectors, white light (W-L) eclipse images and new EUV images obtained with space-borne instruments. We illustrate the mechanisms of low First Ionisation Potential (FIP) emission lines present in the low layers of the solar atmosphere. We identify more precisely low FIP lines both inside and nearby prominences. We characterize in detail the He shells and the solar interface region. Method: 1) High …
issued: 2026-05-07T14:21:11.684845
language: fr
modified: 2026-05-07T14:21:11.684850
contact point: Organization
  fn: CCSD
keyword: chromosphere
keyword: eclipses-totales
keyword: enveloppes-dhelium-ionise
keyword: first-ionisation-potential
keyword: flash-spectra
keyword: formation-des-raies-demission
keyword: infoeu-reposemanticsdoctoralthesis
keyword: interface-photosphere-couronne
keyword: ionized-helium-shells
keyword: photosphere-corona-interface
keyword: physastrsrphysics-physicsastrophysics-astro-phsolar-and-stellar-astrophysics-astro-phsr
keyword: premier-potentiel-dionisation
keyword: sduastrsrsciences-of-the-universe-physicsastrophysics-astro-phsolar-and-stellar-astrophysi
keyword: spectres-eclairs
keyword: theses
keyword: total-solar-eclipses
landing page: https://theses.hal.science/tel-00921889

The solar interface from the photosphere to the chromosphere and corona : contribution of eclipses and EUV filtergrams
type: Distribution
format: HTML
issued: 2026-05-07T14:21:11.686724
modified: 2026-05-07T14:21:11.662490
access URL: https://theses.hal.science/tel-00921889

test_moissonnage_selune
type: Agent