E-Print Archive

There are 3923 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
Spectroscopy of Very Hot Plasma in Non-flaring Parts of a Solar Limb Active Region: Spatial and Temporal Properties  

Susanna Parenti   Submitted: 2017-09-05 04:58

In this work we investigate the thermal structure of an off-limb active region (AR) in various non-flaring areas, as it provides key information on the way these structures are heated. In particular, we concentrate on the very hot component (>3 MK) as it is a crucial element to distinguish between different heating mechanisms. We present an analysis using Fe and Ca emission lines from both the Solar Ultraviolet Measurement of Emitted Radiation (SUMER) on board the Solar and Heliospheric Observatory (SOHO) and the EUV Imaging Spectrometer (EIS) on board Hinode. A data set covering all ionization stages from Fe x to Fe xix has been used for the thermal analysis (both differential emission measure and emission measure, EM). Ca xiv is used for the SUMER-EIS radiometric cross calibration. We show that the very hot plasma is present and persistent almost everywhere in the core of the limb AR. The off-limb AR is clearly structured in Fe xviii. Almost everywhere, the EM analysis reveals plasma at 10 MK (visible in Fe xix emission), which is down to 0.1% of EM of the main 3 MK plasma. We estimate the power-law index of the hot tail of the EM to be between -8.5 and -4.4. However, the question about the possible existence of a small minor peak at around 10 MK remains open. The absence in some part of the AR of the Fe xix and Fe xxiii lines (which fall into our spectral range) enables us to determine an upper limit on the EM at these temperatures. Our results include a new Ca xiv 943.59 ? atomic model.

Authors: Susanna Parenti, Giulio del Zanna, Antonino Petralia, Fabio Reale, Luca Teriaca, Paola Testa, and Helen E. Mason
Projects: SoHO-SUMER

Publication Status: published
Last Modified: 2017-09-06 12:21
Go to main E-Print page  Edit Entry  Download Preprint  Delete Entry 

On the nature of prominence emission observed by SDO/AIA  

Susanna Parenti   Submitted: 2012-05-25 00:53

The Prominence-Corona Transition Region (PCTR) plays a key role in the thermal and pressure equilibrium of solar prominences. Our knowledge of this interface is limited and several major issues remain open, including the thermal structure and, in particular, the maximum temperature of the detectable plasma. The high signal-to-noise ratio of images obtained by the Atmospheric Imaging Assembly (AIA) on NASA's Solar Dynamics Observatory clearly show that prominences are often seen in emission in the 171 and 131 bands. We investigate the temperature sensitivity of these AIA bands for prominence observation, in order to infer the temperature content in an effort to explain the emission. Using the CHIANTI atomic database and previously determined prominence differential emission measure distributions, we build synthetic spectra to establish the main emission-line contributors in the AIA bands. We find that the Fe IX line always dominates the 171 band, even in the absence of plasma at > 106 K temperatures, while the 131 band is dominated by Fe VIII. We conclude that the PCTR has sufficient plasma emitting at > 4 105 K to be detected by AIA.

Authors: Susanna Parenti, Brigitte Schmieder, Petr Heinzel, Leon Golub
Projects: SDO-AIA

Publication Status: accepted on ApJ
Last Modified: 2012-05-25 11:39
Go to main E-Print page  Edit Entry  Download Preprint  Delete Entry 

Solar hydrogen-Lyman continuum observations with SOHO/SUMER  

Susanna Parenti   Submitted: 2006-07-13 03:09

In this work we analyze the emission of the H Lyman continuum (HI LyC) in the Quiet Sun (QS) and a solar prominence, in order to derive information on the temperature of the emitting plasma. We used the spectral atlas obtained with SOHO/SUMER detector A in 1999 (Parenti et al. 2005). The high spectral resolution of this instrument allows a good selection of the continuum, free from emission lines. However, in the HI LyC wavelength domain, the data suffer from large radiometric uncertainties, which lead us to use detector B as a reference. We obtained electron temperatures of 8281 K ± 280 K and 7564 ± 230 K in two separate parts of the prominence.

Authors: S. Parenti, P. Lemaire and J- C. Vial
Projects: SoHO-SUMER

Publication Status: A&A, 2005, 443, 685-689
Last Modified: 2006-07-13 14:21
Go to main E-Print page  Edit Entry  Download Preprint  Delete Entry 

Prominence atlas in the SUMER range 800 - 1250 A: II. Line profile properties and ions identifications  

Susanna Parenti   Submitted: 2006-07-13 03:04

We present a SOHO/SUMER spectral atlas in the 800 - 1250 A range of a prominence and a Quiet Sun (QS) region observed in 1999. The atlas is produced for two separate areas of the prominence. The QS spectrum is used as a reference. This is the first prominence atlas obtained with high spectral resolution (approx 0.044 A). It provides information concerning more than 550 line profiles, in terms of position, total radiance, and FWHM, along with the ion identification. Forty new lines have been identified with respect to previously published spectra.

Authors: S. Parenti, J.- C. Vial and P. Lemaire
Projects: SoHO-SUMER

Publication Status: A&A, 2005, 443, 685-689
Last Modified: 2006-07-13 14:21
Go to main E-Print page  Edit Entry  Download Preprint  Delete Entry 

Modelling the radiative signatures of turbulent heating in coronal loops  

Susanna Parenti   Submitted: 2006-07-13 02:43

The statistical properties of the radiative signature of a coronal loop subject to turbulent heating obtained from a 3-D MHD model are studied. The heating and cooling of a multi-strand loop is modelled and synthetic spectra for Fe XII 195.12 A, Fe XV 284.163 A and Fe XIX 1118.06 A are calculated, so covering a wide temperature range. The results show that the statistical properties of the thermal and radiative energies partially reflect those of the heating function in that power law distributions are transmitted, but with very significant changes in the power law indices. There is a strong dependence on the sub-loop geometry. Only high temperature radiation (approx 107 K) preserves reasonably precise information on the heating function.

Authors: S. Parenti, E. Buchlin, P. J. Cargill,S. Galtier and J-C. Vial
Projects: None

Publication Status: accepted
Last Modified: 2006-07-13 14:21
Go to main E-Print page  Edit Entry  Delete Entry 


Key
Go to main E-Print pageGo to main E-Print page.
Download PreprintDownload Preprint.
Submitter's HomepageSubmitters Homepage.
Edit EntryEdit Entry.
Delete AbstractDelete abstract.

Abstracts by Author
Spectroscopy of Very Hot Plasma in Non-flaring Parts of a Solar Limb Active Region: Spatial and Temporal Properties
On the nature of prominence emission observed by SDO/AIA
Solar hydrogen-Lyman continuum observations with SOHO/SUMER
Prominence atlas in the SUMER range 800 - 1250 A: II. Line profile properties and ions identifications
Modelling the radiative signatures of turbulent heating in coronal loops

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