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ESPOS videos
European Solar Physics Online Seminars
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https://espos.stream
Department
Field of research
Natural Sciences (Astrophysics and Astrononmy)
Email
shahin.jafarzadeh@astro.uio.no
My OpenAccess portfolio
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High-resolution spectroscopy of a minifilament eruption | Ioannis Kontogiannis
Natural Sciences (Astrophysics and Astrononmy)
311 views
Date of upload:
21.10.2021
Co-author:
Caption:
Minifilaments are miniature versions of filaments, first observed in H-alpha filtergrams of quiet Sun. Recent studies have showcased their association with small-scale eruptive events, highlighting their importance in energetic processes of the quiet Sun. We present the first detailed study of such an event, using high-cadence, high-spectral resolution imaging observations. The minifilament formed between small-scale, opposite-polarity magnetic concentrations and erupted within an hour after its appearance in H-alpha, exhibiting a twisted, thread-like structure. Its eruption took place in two phases (slow and fast), producing a coronal dimming, while part of the erupting material returned to the chromosphere. The observed similarities to large-scale filament eruptions indicate the action o
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On the formation of solar wind & switchbacks, and quiet Sun heating | Vishal Upendran
Natural Sciences (Astrophysics and Astrononmy)
315 views
Date of upload:
22.12.2021
Co-author:
Caption:
The solar coronal heating in quiet Sun (QS) and coronal holes (CH), including solar wind formation, are intimately tied by magnetic field dynamics. Thus, a detailed comparative study of these regions is needed to understand the underlying physical processes. CHs are known to have subdued intensity and larger blueshifts in the corona. This work investigates the similarities and differences between CHs and QS in the chromosphere using the Mg II h & k, C II lines, and transition region using Si IV line, for regions with identical absolute magnetic flux density (|B|). See more info at https://espos.stream/2021/12/16/Upendran/.
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Formation and disappearance of a penumbra: Recent results | Mariarita Murabito
Natural Sciences (Astrophysics and Astrononmy)
261 views
Date of upload:
23.02.2022
Co-author:
Caption:
The physical conditions resulting in the formation and disappearance of penumbral regions are poorly understood. We investigated these conditions by using high-resolution spectropolarimetric observations of a sunspot penumbra from different instruments at ground- and space-based telescopes, namely the SST/CRISP, SDO/HMI, and Hinode/SP. The studied data allowed us to assess the evolution of the magnetic and velocity properties of plasma in the observed region and to analyze the role of several processes found therein. The penumbra forms only on one side of the observed region, characterized by the absence of an overlying magnetic canopy. The penumbra later disappears progressively in time and space. This final evolution of the studied region seems to be governed by the presence of moving ma
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Upflows in the quiet Sun and coronal holes | Conrad Schwanitz
Natural Sciences (Astrophysics and Astrononmy)
357 views
Date of upload:
28.02.2022
Co-author:
Caption:
Recent observations from Solar Orbiter have emphasised the importance of small and short-lived phenomena in the solar atmosphere. They have shown small extreme-ultraviolet brightenings in the solar corona, which appear very frequently. Previously, Parker Solar Probe has revealed a highly dynamic structure in the solar wind’s magnetic field, which are referred to as switchbacks. Those results raise the question of the importance of small-scale phenomena and their potential contribution to the solar wind. We have analysed 14 coronal upflows, which were derived as blue shifts in spectroscopic data and examined the potential sources for each upflow. This was done by using Hinode/EIS rasters and calculating the Doppler velocities for the Fe XII line. Events, which are stronger blue-shifted than

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