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Article
Open AccessOn the Physical Nature of the so-Called Prominence Tornadoes
The term ‘tornado’ has been used in recent years to describe several solar phenomena, from large-scale eruptive prominences to small-scale photospheric vortices. It has also been applied to the generally stabl...
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Article
Extreme-Ultraviolet Wave and Accompanying Loop Oscillations
We present the observations of an extreme-ultraviolet (EUV) wave, which originated from the active region (AR) NOAA 12887 on 28 October 2021, and its impact on neighboring loops. The event was observed by the Atm...
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Article
Open AccessAnalysis of the Evolution of a Multi-Ribbon Flare and Failed Filament Eruption
How filaments form and erupt are topics about which solar researchers have wondered for more than a century and they are still open to debate. We present observations of a filament formation, its failed erupti...
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Article
Reminiscences
I would like to thank my Solar Physics colleagues for asking me to write this chapter on my professional life. My main interest has always been focused on the Sun, our star, from the heating of the corona, to ...
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Article
Open AccessSolar Ultraviolet Bursts
The term “ultraviolet (UV) burst” is introduced to describe small, intense, transient brightenings in ultraviolet images of solar active regions. We inventorize their properties and provide a definition based ...
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Article
Open AccessCoronal loops, flare ribbons and aurora during slip-running
Solar two ribbon flares are commonly explained by magnetic field reconnections in the low corona. During the reconnection energetic particles (electrons and protons) are accelerated from the reconnection site....
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Article
Is Pre-Eruptive Null Point Reconnection Required for Triggering Eruptions?
We study the magnetic field evolution and topology of the active region NOAA 10486 before the 3B/X1.2 flare of October 26, 2003, using observational data from the French–Italian THEMIS telescope, the Michelson...
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Article
Magnetic source regions of coronal mass ejections
The majority of flare activity arises in active regions which contain sunspots, while Coronal Mass Ejection (CME) activity can also originate from decaying active regions and even so-called quiet solar regions...
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Article
Magnetic changes observed in the formation of two filaments in a complex active region: TRACE and MSDP observations
This paper is focused on the formation of two filaments in a complex center of decaying active regions (AR 8329 and AR 8326), located in the northern hemisphere. The observations were obtained in Hα by the Mul...
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Article
Multi-wavelength study of a high-latitude EUV filament
A large filament was observed during a multi-wavelength coordinated campaign on June 19, 1998 in the Hα line with the Swedish Vacuum Solar Telescope (SVST) at La Palma, in the coronal lines Fe ix/x 171 Å and F...
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Article
Filament activation and magnetic reconnection
A curved filament in a decaying active region (AR 8329) was observed on 9 September 1998 with a combination of several instruments. The main data base is a 4-hour long time series of 1 min cadence using the Lo...
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Article
A Relationship Between Transition Region Brightenings, Abundances, and Magnetic Topology
We present multi-instrument observations of active region (AR) 8048, made between 3 June and 5 June 1997, as part of the SOHO Joint Observing Program 33. This AR has a sigmoid-like global shape and undergoes t...
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Chapter
From One Joso to Another...
Her courtesy, her elegance, her ability to chair a meeting....I met her only lately, at the occasion of a JOSO meeting at Berlin, in 1991. She was then in the chair.The following year, I succeded her...What an...
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Article
OPTICAL AND RADIO SPECTRAL ANALYSIS OF A RECURRENT SURGE
Coordinated observations obtained at Meudon (MSDP) and at Ondřejov provide surge spectra in optical range (Hα, Hβ, Hγ, Hµ, Ca H and K lines) and in radio range. The MSDP data allowed us to follow the time evol...
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Chapter and Conference Paper
Flows through the magnetically structured solar atmosphere
The upper solar atmosphere until three solar radii is controlled by the magnetic field. The plasma β (P kin/P magn) is decreasing with increasing altitude in the low coro...
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Chapter
Fine Structures of the Solar Chromosphere
We summarize studies of the spatial and temporal behavior of the physical parameters of the chromospheric fine structures called mottles (or disk spicules), using high spatial resolution observations obtained ...
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Chapter and Conference Paper
The Role of the Observatoire de Paris, Meudon in Providing Astronomical Information
The three research centres (Paris, Meudon, Nancay) receive groups totalling about 10 000 visitors per year, consisting primarily of school-children and the general public. Tours begin with a slide-show and the...
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Article
Fractionation of particulate material from maize coleoptile homogenates with polyethylene glycol
Polyethyleneglycol (PEG) has been used to sediment particulate material from maize coleoptile homogenates at low centrifugal forces. The resuspended sediments were used for N-1-naphthylphthalamic acid (NPA)-bi...
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Article
Wave propagation in the photosphere
Using a 32 minutes sequence of observation, brightness and velocity fluctuations in the wings of the Mgi line at 5172.7 Å and Fe ii line at 5197.578 Å are analysed. The analysis of phase shifts and amplitude rati...