Seminars


6 Aprilie 2017

Marilena Mierla

 CMEs: reconstructie 3D si propagare


 

8 July 2015, 11:00 Local time

Stephane Regnier (Northumbria University, UK)

 

Heating and cooling of multistranded coronal loops: a temperature diagnostic

 

Abstract

 

Coronal loops are fine structures guiding the plasma and structuring active regions. They evidence cycles of heating and cooling observed as variations in the intensity of EUV spectral lines and the associated Dopplershifts. We here address the questions of what are the signatures of heating and cooling events in the corona? and what can we learn from these signatures? We describe the observational signatures of heating events by considering that a coronal loop can be described by a collection of individual strands subject to a high-frequency random heating mimicking the nanoflare model. The intensity and Dopplershift variations are provided for current instruments such as Hinode/EIS and SDO/AIA. We deduce a temperature diagnostic in Hinode/EIS using the fact that cool spectral lines are redshift dominated and hot spectral lines are blueshift dominated. Regarding the cooling of a coronal loop, the temperature of the plasma before the cooling can be estimated. In addition, we can reconstruct the cooling profile of the loop. Those temperature diagnostics are validated/compared to flare observations and long-term oscillating loops.

 

 


20 septembrie 2013, ora 13

Liliana Dumitru

Helicitatea in regiunile active


31 mai 2013, ora 12

Sergiu Lupu

CONTRIBUŢII LA STUDIUL ERORILOR ORBITALE ALE SATELITILOR GPS DATORATE PERTURBATIILOR NEGRAVITATIONALE


24 mai 2013, ora 12

Liliana Dumitru

Regiuni active: formare, evolutie


24 mai 2013, ora 11

Liliana Dumitru

Fenomene eruptive in atmosfera Soarelui