Coronal equatorial rotation during solar cycle 23: radial variation and connections with helioseismology

Mancuso, Salvatore; Giordano, S.

doi:10.1051/0004-6361/201117869

Cited by 8 publications

(10 citation statements)

References 42 publications

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“…Coronal observations from different latitudes also allow a novel approach to the study of the degree of rigidity of the coronal rotation with heliodistance (Lewis et al 1999;Giordano & Mancuso 2008;Mancuso & Giordano 2012), by tracing the motion of persistent coronal features on the plane of the sky as this moves toward the solar equatorial plane when the spacecraft latitude increases.…”

Section: Global Evolution Of the Streamer Beltmentioning

confidence: 99%

Metis: the Solar Orbiter visible light and ultraviolet coronal imager

Antonucci

Romoli

Andretta

et al. 2020

A&A

129

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Aims. Metis is the first solar coronagraph designed for a space mission and is capable of performing simultaneous imaging of the off-limb solar corona in both visible and UV light. The observations obtained with Metis aboard the Solar Orbiter ESA-NASA observatory will enable us to diagnose, with unprecedented temporal coverage and spatial resolution, the structures and dynamics of the full corona in a square field of view (FoV) of ±2.9 • in width, with an inner circular FoV at 1.6 • , thus spanning the solar atmosphere from 1.7 R to about 9 R , owing to the eccentricity of the spacecraft orbit. Due to the uniqueness of the Solar Orbiter mission profile, Metis will be able to observe the solar corona from a close (0.28 AU, at the closest perihelion) vantage point, achieving increasing out-of-ecliptic views with the increase of the orbit inclination over time. Moreover, observations near perihelion, during the phase of lower rotational velocity of the solar surface relative to the spacecraft, allow longer-term studies of the off-limb coronal features, thus finally disentangling their intrinsic evolution from effects due to solar rotation. Methods. Thanks to a novel occultation design and a combination of a UV interference coating of the mirrors and a spectral bandpass filter, Metis images the solar corona simultaneously in the visible light band, between 580 and 640 nm, and in the UV H i Lyman-α line at 121.6 nm. The visible light channel also includes a broadband polarimeter able to observe the linearly polarised component of the K corona. The coronal images in both the UV H i Lyman-α and polarised visible light are obtained at high spatial resolution with a spatial scale down to about 2000 km and 15000 km at perihelion, in the cases of the visible and UV light, respectively. A temporal resolution down to 1 second can be achieved when observing coronal fluctuations in visible light. Results. The Metis measurements, obtained from different latitudes, will allow for complete characterisation of the main physical parameters and dynamics of the electron and neutral hydrogen/proton plasma components of the corona in the region where the solar wind undergoes the acceleration process and where the onset and initial propagation of coronal mass ejections (CMEs) take place. The near-Sun multi-wavelength coronal imaging performed with Metis, combined with the unique opportunities offered by the Solar Orbiter mission, can effectively address crucial issues of solar physics such as: the origin and heating/acceleration of the fast and slow solar wind streams; the origin, acceleration, and transport of the solar energetic particles; and the transient ejection of coronal mass and its evolution in the inner heliosphere, thus significantly improving our understanding of the region connecting the Sun to the heliosphere and of the processes generating and driving the solar wind and coronal mass ejections. Conclusions. This paper presents the scientific objectives and requirements, the overall optical design of the Metis instrument, t...

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Section: Global Evolution Of the Streamer Beltmentioning

confidence: 99%

Metis: the Solar Orbiter visible light and ultraviolet coronal imager

Antonucci

Romoli

Andretta

et al. 2020

A&A

129

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“…For comparison, the typical intensities in streamers at solar minimum and maximum and in coronal hole are also plotted. These reference values are determined from the UVCS intensity Carrington maps used for coronal rotation studies [ Giordano and Mancuso , ; Mancuso and Giordano , , ]. The O VI 1032 Å (left panel) and C III 977 Å (right panel) line intensities in the UVCS CMEs are shown in Figure .…”

Section: Uvcs Cme Catalogmentioning

confidence: 99%

UVCS/SOHO catalog of coronal mass ejections from 1996 to 2005: Spectroscopic proprieties

et al. 2013

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[1] Ultraviolet spectra of the extended solar corona have been routinely obtained by SOHO/UltraViolet Coronagraph Spectrometer (UVCS) since 1996. Sudden variations of spectral parameters are mainly due to the detection of coronal mass ejections (CMEs) crossing the instrumental slit. We present a catalog of CME ultraviolet spectra based upon a systematic search of events in the Large Angle and Spectrometric Coronagraph (LASCO) CME catalog, and we discuss their statistical properties. Our catalog includes 1059 events through the end of 2005, covering nearly a full solar cycle. It is available online at the URL http://solarweb.oato.inaf.it/UVCS_CME and embedded in the online LASCO CME catalog (http://cdaw.gsfc.nasa.gov/CME_list). The emission lines observed provide diagnostics of CME plasma parameters, such as the light-of-sight velocity, density, and temperature and allow to link the CME onset data to the extended corona white-light images. The catalog indicates whether there are clear signatures of features such as shock waves, current sheets, O VI flares, helical motions, and which part of the CME structures (front, cavity, or prominence material) are detected. The most common detected structure is the cool prominence material (in about 70% of the events). For each event, the catalog also contains movies, images, plots, and information relevant to address detailed scientific investigations. The number of events detected in UV is about one tenth of the LASCO CMEs and about one fourth of the halo events. We find that UVCS tends to detect faster, more massive, and energetic CME than LASCO, and for about 40% of the events, it has been possible to determine the plasma light-of-sight velocity.

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“…In general, during solar maximum, the coronal magnetic structures were observed to rotate much faster at all latitudes, and less differentially, than the underlying small-scale magnetic structures linked to the photospheric plasma. A striking significant positive correlation was finally discovered by Mancuso and Giordano [3] between the variations in the residual rotation rates of the coronal and sub-photospheric equatorial plasma, suggesting that the observed variations in the coronal rotation rate reflect the dynamic changes inferred within the near-surface shear layer, where the tracer structures responsible for the observed coronal emission are thus most probably anchored. Projection effects could certainly play a major role in the interpretation of the results presented in the previous works.…”

Section: Introductionmentioning

confidence: 78%

“…1 show a clear modulation, which can be readily attributed to the rotation of persistent features through several consecutive rotations. Results can be found in papers [1–3] .…”

Section: Data Reduction and Analysismentioning

confidence: 99%

“…In the past few years, the analysis of a full decade of data obtained by telescopes aboard the Solar and Heliospheric Observatory (SOHO; [4] ) spacecraft, has allowed to study the temporal variation in the coronal rotation rate for the whole solar cycle 23. In particular, time-series observations of the coronal O VI 1032 Å spectral line intensity provided by the UltraViolet Coronagraph Spectrometer (UVCS/SOHO; [5] ) telescope on board SOHO have been effectively used to study the differential rotation of the solar corona during minimum [1] and maximum [2] solar activity and throughout the whole solar cycle [3] . The work of Giordano and Mancuso [1] confirmed the already established result that the corona, during minimum activity, tends to rotate with a less pronounced differential rotation than the plasma of the photosphere.…”

Section: Introductionmentioning

confidence: 99%

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Influence of projection effects on the observed differential rotation rate in the UV corona

Mancuso

Giordano

2013

Journal of Advanced Research

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Following previous investigations by Giordano and Mancuso [1] and Mancuso and Giordano [2,3] on the differential rotation of the solar corona as obtained through the analysis of the intensity time series of the O VI 1032 Å spectral line observed by the UVCS/SOHO telescope during solar cycle 23, we analysed the possible influence of projection effects of extended coronal structures on the observed differential rotation rate in the ultraviolet corona. Through a simple geometrical model, we found that, especially at higher latitudes, the differential rotation may be less rigid than observed, since features at higher latitudes could be actually linked to much lower coronal structures due to projection effects. At solar maximum, the latitudinal rigidity of the UV corona, with respect to the differential rotating photosphere, has thus to be considered as an upper limit of the possible rigidity. At solar minimum and near the equatorial region throughout the solar cycle, projection effects are negligible.

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Coronal equatorial rotation during solar cycle 23: radial variation and connections with helioseismology

Cited by 8 publications

References 42 publications

Metis: the Solar Orbiter visible light and ultraviolet coronal imager

Metis: the Solar Orbiter visible light and ultraviolet coronal imager

UVCS/SOHO catalog of coronal mass ejections from 1996 to 2005: Spectroscopic proprieties

Influence of projection effects on the observed differential rotation rate in the UV corona

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