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J. L. Ballester - One of the best experts on this subject based on the ideXlab platform.
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Prominence oscillations
Living Reviews in Solar Physics, 2018Co-Authors: Iñigo Arregui, Ramón Oliver, J. L. BallesterAbstract:Prominences are intriguing, but poorly understood, magnetic structures of the solar corona. The dynamics of solar Prominences has been the subject of a large number of studies, and of particular interest is the study of Prominence oscillations. Ground- and space-based observations have confirmed the presence of oscillatory motions in Prominences and they have been interpreted in terms of magnetohydrodynamic waves. This interpretation opens the door to perform Prominence seismology, whose main aim is to determine physical parameters in magnetic and plasma structures (Prominences) that are difficult to measure by direct means. Here, we review the observational information gathered about Prominence oscillations as well as the theoretical models developed to interpret small and large amplitude oscillations and their temporal and spatial attenuation. Finally, several Prominence seismology applications are presented.
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Prominence Seismology
Proceedings of the International Astronomical Union, 2013Co-Authors: J. L. BallesterAbstract:AbstractQuiescent solar Prominences are cool and dense plasma clouds located inside the hot and less dense solar corona. They are highly dynamic structures displaying flows, instabilities, oscillatory motions, etc. The oscillations have been mostly interpreted in terms of magnetohydrodynamic (MHD) waves, which has allowed to perform Prominence seismology as a tool to determine Prominence physical parameters difficult to measure. Here, several Prominence seismology applications to large and small amplitude oscillations are reviewed.
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Prominence Oscillations
Living Reviews in Solar Physics, 2012Co-Authors: Iñigo Arregui, Ramón Oliver, J. L. BallesterAbstract:Prominences are intriguing, but poorly understood, magnetic structures of the solar corona. The dynamics of solar Prominences has been the subject of a large number of studies, and of particular interest is the study of Prominence oscillations. Ground- and space-based observations have confirmed the presence of oscillatory motions in Prominences and they have been interpreted in terms of magnetohydrodynamic (MHD) waves. This interpretation opens the door to perform Prominence seismology, whose main aim is to determine physical parameters in magnetic and plasma structures (Prominences) that are difficult to measure by direct means. Here, we review the observational information gathered about Prominence oscillations as well as the theoretical models developed to interpret small amplitude oscillations and their temporal and spatial attenuation. Finally, several Prominence seismology applications are presented.
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Prominence seismology
2012Co-Authors: I. Arregui, J. L. Ballester, Ramón Oliver, Roberto Soler, J. TerradasAbstract:Given the difficulty in directly determining Prominence physical parameters from observations, Prominence seismology stands as an alternative method to probe the nature of these structures. We show recent examples of the application of magnetohydrodynamic (MHD) seismology techniques to infer physical parameters in Prominence plasmas. They are based on the application of inversion techniques using observed periods, damping times, and plasma flow speeds of Prominence thread oscillations. The contribution of Hinode to the subject has been of central importance. We show an example based on data obtained with Hinode's Solar Optical Telescope. Observations show an active region limb Prominence, composed by a myriad of thin horizontal threads that flow following a path parallel to the photosphere and display synchronous vertical oscillations. The coexistence of waves and flows can be firmly established. By making use of an interpretation based on transverse MHD kink oscillations, a seismological analysis of this event is performed. It is shown that the combination of high quality Hinode observations and proper theoretical models allows flows and waves to become two useful characteristics for our understanding of the nature of solar Prominences.
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physics of solar Prominences ii magnetic structure and dynamics
arXiv: Solar and Stellar Astrophysics, 2010Co-Authors: D H Mackay, J. L. Ballester, Judith T Karpen, B Schmieder, G AulanierAbstract:Observations and models of solar Prominences are reviewed. We focus on non-eruptive Prominences, and describe recent progress in four areas of Prominence research: (1) magnetic structure deduced from observations and models, (2) the dynamics of Prominence plasmas (formation and flows), (3) Magneto-hydrodynamic (MHD) waves in Prominences and (4) the formation and large-scale patterns of the filament channels in which Prominences are located. Finally, several outstanding issues in Prominence research are discussed, along with observations and models required to resolve them.
B Schmieder - One of the best experts on this subject based on the ideXlab platform.
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Modelling and observations: Comparison of the magnetic field properties in a Prominence
Astronomy and Astrophysics - A&A, 2020Co-Authors: D. Mackay, B Schmieder, A. López AristeAbstract:Context. Direct magnetic field measurements in solar Prominences occur infrequently and are difficult to make and interpret. As a consequence, alternative methods are needed to derive the main properties of the magnetic field that supports the Prominence mass. This is important for our understanding of solar Prominences, but also for understanding how eruptive Prominences may affect space weather. Aims. We present the first direct comparison of the magnetic field strength derived from spectro-polarimetric observations of a solar Prominence, with corresponding results from a theoretical flux rope model constructed from on-disc normal component magnetograms. Methods. We first used spectro-polarimetric observations of a Prominence obtained with the magnetograph THEMIS operating in the Canary Islands to derive the magnetic field of the observed Prominence by inverting the Stokes parameters measured in the He D3 line. Next, we constructed two data-constrained non-linear force-free field (NLFFF) models of the same Prominence. In one model we assumed a strongly twisted flux rope solution, and in the other a weakly twisted flux rope solution. Results. The physical extent of the Prominence at the limb (height and length) is best reproduced with the strongly twisted flux rope solution. The line-of-sight average of the magnetic field for the strongly twisted solution results in a magnetic field that has a magnitude of within a factor of 1−2 of the observed magnetic field strength. For the peak field strength along the line of sight, an agreement to within 20% of the observations is obtained for the strongly twisted solution. The weakly twisted solution produces significantly lower magnetic field strengths and gives a poor agreement with the observations. Conclusions. The results of this first comparison are promising. We found that the flux rope insertion method of producing a NLFFF is able to deduce the overall properties of the magnetic field in an observed Prominence.
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Reconstruction of a helical Prominence in 3D from IRIS spectra and images
Astronomy and Astrophysics - A&A, 2017Co-Authors: B Schmieder, N Labrosse, M. Zapior, A. López Ariste, P. Levens, R. GravetAbstract:Context. Movies of Prominences obtained by space instruments e.g. the Solar Optical Telescope (SOT) aboard the Hinode satellite and the Interface Region Imaging Spectrograph (IRIS) with high temporal and spatial resolution revealed the tremendous dynamical nature of Prominences. Knots of plasma belonging to Prominences appear to travel along both vertical and horizontal thread-like loops, with highly dynamical nature.Aims. The aim of the paper is to reconstruct the 3D shape of a helical Prominence observed over two and a half hours by IRIS.Methods. From the IRIS Mg ii k spectra we compute Doppler shifts of the plasma inside the Prominence and from the slit-jaw images (SJI) we derive the transverse field in the plane of the sky. Finally we obtain the velocity vector field of the knots in 3D.Results.We reconstruct the real trajectories of nine knots travelling along ellipses.Conclusions. The spiral-like structure of the Prominence observed in the plane of the sky is mainly due to the projection effect of long arches of threads (up to 8 × 104 km). Knots run along more or less horizontal threads with velocities reaching 65 km s-1. The dominant driving force is the gas pressure.
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magnetic field in atypical Prominence structures bubble tornado and eruption
The Astrophysical Journal, 2016Co-Authors: P J Levens, B Schmieder, Lopez A Ariste, N Labrosse, K Dalmasse, B GellyAbstract:Spectropolarimetric observations of Prominences have been obtained with the THEMIS telescope during four years of coordinated campaigns. Our aim is now to understand the conditions of the cool plasma and magnetism in "atypical" Prominences, namely when the measured inclination of the magnetic field departs, to some extent, from the predominantly horizontal field found in "typical" Prominences. What is the role of the magnetic field in these Prominence types? Are plasma dynamics more important in these cases than the magnetic support? We focus our study on three types of "atypical" Prominences (tornadoes, bubbles, and jet-like Prominence eruptions) that have all been observed by THEMIS in the He i D3 line, from which the Stokes parameters can be derived. The magnetic field strength, inclination, and azimuth in each pixel are obtained by using the inversion method of principal component analysis on a model of single scattering in the presence of the Hanle effect. The magnetic field in tornadoes is found to be more or less horizontal, whereas for the eruptive Prominence it is mostly vertical. We estimate a tendency toward higher values of magnetic field strength inside the bubbles than outside in the surrounding Prominence. In all of the models in our database, only one magnetic field orientation is considered for each pixel. While sufficient for most of the main Prominence body, this assumption appears to be oversimplified in atypical Prominence structures. We should consider these observations as the result of superposition of multiple magnetic fields, possibly even with a turbulent field component.
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on the nature of Prominence emission observed by sdo aia
The Astrophysical Journal, 2012Co-Authors: Susanna Parenti, B Schmieder, P. Heinzel, Leon GolubAbstract: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 shows that Prominences are often seen in emission in the 171 and 131 bands. We investigate the temperature sensitivity of these AIA bands for Prominence observations, 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.
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Physics of Solar Prominences: I—Spectral Diagnostics and Non-LTE Modelling
Space Science Reviews, 2010Co-Authors: N Labrosse, B Schmieder, S. Gunár, P. Heinzel, J.-c. Vial, T. Kucera, S. Parenti, G. KilperAbstract:This review paper outlines background information and covers recent advances made via the analysis of spectra and images of Prominence plasma and the increased sophistication of non-LTE ( i.e. when there is a departure from Local Thermodynamic Equilibrium) radiative transfer models. We first describe the spectral inversion techniques that have been used to infer the plasma parameters important for the general properties of the Prominence plasma in both its cool core and the hotter Prominence-corona transition region. We also review studies devoted to the observation of bulk motions of the Prominence plasma and to the determination of Prominence mass. However, a simple inversion of spectroscopic data usually fails when the lines become optically thick at certain wavelengths. Therefore, complex non-LTE models become necessary. We thus present the basics of non-LTE radiative transfer theory and the associated multi-level radiative transfer problems. The main results of one- and two-dimensional models of the Prominences and their fine-structures are presented. We then discuss the energy balance in various Prominence models. Finally, we outline the outstanding observational and theoretical questions, and the directions for future progress in our understanding of solar Prominences.
N Labrosse - One of the best experts on this subject based on the ideXlab platform.
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Reconstruction of a helical Prominence in 3D from IRIS spectra and images
Astronomy and Astrophysics - A&A, 2017Co-Authors: B Schmieder, N Labrosse, M. Zapior, A. López Ariste, P. Levens, R. GravetAbstract:Context. Movies of Prominences obtained by space instruments e.g. the Solar Optical Telescope (SOT) aboard the Hinode satellite and the Interface Region Imaging Spectrograph (IRIS) with high temporal and spatial resolution revealed the tremendous dynamical nature of Prominences. Knots of plasma belonging to Prominences appear to travel along both vertical and horizontal thread-like loops, with highly dynamical nature.Aims. The aim of the paper is to reconstruct the 3D shape of a helical Prominence observed over two and a half hours by IRIS.Methods. From the IRIS Mg ii k spectra we compute Doppler shifts of the plasma inside the Prominence and from the slit-jaw images (SJI) we derive the transverse field in the plane of the sky. Finally we obtain the velocity vector field of the knots in 3D.Results.We reconstruct the real trajectories of nine knots travelling along ellipses.Conclusions. The spiral-like structure of the Prominence observed in the plane of the sky is mainly due to the projection effect of long arches of threads (up to 8 × 104 km). Knots run along more or less horizontal threads with velocities reaching 65 km s-1. The dominant driving force is the gas pressure.
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magnetic field in atypical Prominence structures bubble tornado and eruption
The Astrophysical Journal, 2016Co-Authors: P J Levens, B Schmieder, Lopez A Ariste, N Labrosse, K Dalmasse, B GellyAbstract:Spectropolarimetric observations of Prominences have been obtained with the THEMIS telescope during four years of coordinated campaigns. Our aim is now to understand the conditions of the cool plasma and magnetism in "atypical" Prominences, namely when the measured inclination of the magnetic field departs, to some extent, from the predominantly horizontal field found in "typical" Prominences. What is the role of the magnetic field in these Prominence types? Are plasma dynamics more important in these cases than the magnetic support? We focus our study on three types of "atypical" Prominences (tornadoes, bubbles, and jet-like Prominence eruptions) that have all been observed by THEMIS in the He i D3 line, from which the Stokes parameters can be derived. The magnetic field strength, inclination, and azimuth in each pixel are obtained by using the inversion method of principal component analysis on a model of single scattering in the presence of the Hanle effect. The magnetic field in tornadoes is found to be more or less horizontal, whereas for the eruptive Prominence it is mostly vertical. We estimate a tendency toward higher values of magnetic field strength inside the bubbles than outside in the surrounding Prominence. In all of the models in our database, only one magnetic field orientation is considered for each pixel. While sufficient for most of the main Prominence body, this assumption appears to be oversimplified in atypical Prominence structures. We should consider these observations as the result of superposition of multiple magnetic fields, possibly even with a turbulent field component.
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Physics of Solar Prominences: I—Spectral Diagnostics and Non-LTE Modelling
Space Science Reviews, 2010Co-Authors: N Labrosse, B Schmieder, S. Gunár, P. Heinzel, J.-c. Vial, T. Kucera, S. Parenti, G. KilperAbstract:This review paper outlines background information and covers recent advances made via the analysis of spectra and images of Prominence plasma and the increased sophistication of non-LTE ( i.e. when there is a departure from Local Thermodynamic Equilibrium) radiative transfer models. We first describe the spectral inversion techniques that have been used to infer the plasma parameters important for the general properties of the Prominence plasma in both its cool core and the hotter Prominence-corona transition region. We also review studies devoted to the observation of bulk motions of the Prominence plasma and to the determination of Prominence mass. However, a simple inversion of spectroscopic data usually fails when the lines become optically thick at certain wavelengths. Therefore, complex non-LTE models become necessary. We thus present the basics of non-LTE radiative transfer theory and the associated multi-level radiative transfer problems. The main results of one- and two-dimensional models of the Prominences and their fine-structures are presented. We then discuss the energy balance in various Prominence models. Finally, we outline the outstanding observational and theoretical questions, and the directions for future progress in our understanding of solar Prominences.
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Physics of Solar Prominences: I—Spectral Diagnostics and Non-LTE Modelling
Space Science Reviews, 2010Co-Authors: N Labrosse, B Schmieder, S. Gunár, P. Heinzel, J.-c. Vial, T. Kucera, S. Parenti, G. KilperAbstract:This review paper outlines background information and covers recent advances made via the analysis of spectra and images of Prominence plasma and the increased sophistication of non-LTE ( i.e. when there is a departure from Local Thermodynamic Equilibrium) radiative transfer models. We first describe the spectral inversion techniques that have been used to infer the plasma parameters important for the general properties of the Prominence plasma in both its cool core and the hotter Prominence-corona transition region. We also review studies devoted to the observation of bulk motions of the Prominence plasma and to the determination of Prominence mass. However, a simple inversion of spectroscopic data usually fails when the lines become optically thick at certain wavelengths. Therefore, complex non-LTE models become necessary. We thus present the basics of non-LTE radiative transfer theory and the associated multi-level radiative transfer problems. The main results of one- and two-dimensional models of the Prominences and their fine-structures are presented. We then discuss the energy balance in various Prominence models. Finally, we outline the outstanding observational and theoretical questions, and the directions for future progress in our understanding of solar Prominences.
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physics of solar Prominences i spectral diagnostics and non lte modelling
arXiv: Solar and Stellar Astrophysics, 2010Co-Authors: N Labrosse, B Schmieder, S. Gunár, P. Heinzel, J.-c. Vial, S. Parenti, Therese A Kucera, G. KilperAbstract:This review paper outlines background information and covers recent advances made via the analysis of spectra and images of Prominence plasma and the increased sophistication of non-LTE (ie when there is a departure from Local Thermodynamic Equilibrium) radiative transfer models. We first describe the spectral inversion techniques that have been used to infer the plasma parameters important for the general properties of the Prominence plasma in both its cool core and the hotter Prominence-corona transition region. We also review studies devoted to the observation of bulk motions of the Prominence plasma and to the determination of Prominence mass. However, a simple inversion of spectroscopic data usually fails when the lines become optically thick at certain wavelengths. Therefore, complex non-LTE models become necessary. We thus present the basics of non-LTE radiative transfer theory and the associated multi-level radiative transfer problems. The main results of one- and two-dimensional models of the Prominences and their fine-structures are presented. We then discuss the energy balance in various Prominence models. Finally, we outline the outstanding observational and theoretical questions, and the directions for future progress in our understanding of solar Prominences.
G. Kilper - One of the best experts on this subject based on the ideXlab platform.
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Physics of Solar Prominences: I—Spectral Diagnostics and Non-LTE Modelling
Space Science Reviews, 2010Co-Authors: N Labrosse, B Schmieder, S. Gunár, P. Heinzel, J.-c. Vial, T. Kucera, S. Parenti, G. KilperAbstract:This review paper outlines background information and covers recent advances made via the analysis of spectra and images of Prominence plasma and the increased sophistication of non-LTE ( i.e. when there is a departure from Local Thermodynamic Equilibrium) radiative transfer models. We first describe the spectral inversion techniques that have been used to infer the plasma parameters important for the general properties of the Prominence plasma in both its cool core and the hotter Prominence-corona transition region. We also review studies devoted to the observation of bulk motions of the Prominence plasma and to the determination of Prominence mass. However, a simple inversion of spectroscopic data usually fails when the lines become optically thick at certain wavelengths. Therefore, complex non-LTE models become necessary. We thus present the basics of non-LTE radiative transfer theory and the associated multi-level radiative transfer problems. The main results of one- and two-dimensional models of the Prominences and their fine-structures are presented. We then discuss the energy balance in various Prominence models. Finally, we outline the outstanding observational and theoretical questions, and the directions for future progress in our understanding of solar Prominences.
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Physics of Solar Prominences: I—Spectral Diagnostics and Non-LTE Modelling
Space Science Reviews, 2010Co-Authors: N Labrosse, B Schmieder, S. Gunár, P. Heinzel, J.-c. Vial, T. Kucera, S. Parenti, G. KilperAbstract:This review paper outlines background information and covers recent advances made via the analysis of spectra and images of Prominence plasma and the increased sophistication of non-LTE ( i.e. when there is a departure from Local Thermodynamic Equilibrium) radiative transfer models. We first describe the spectral inversion techniques that have been used to infer the plasma parameters important for the general properties of the Prominence plasma in both its cool core and the hotter Prominence-corona transition region. We also review studies devoted to the observation of bulk motions of the Prominence plasma and to the determination of Prominence mass. However, a simple inversion of spectroscopic data usually fails when the lines become optically thick at certain wavelengths. Therefore, complex non-LTE models become necessary. We thus present the basics of non-LTE radiative transfer theory and the associated multi-level radiative transfer problems. The main results of one- and two-dimensional models of the Prominences and their fine-structures are presented. We then discuss the energy balance in various Prominence models. Finally, we outline the outstanding observational and theoretical questions, and the directions for future progress in our understanding of solar Prominences.
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physics of solar Prominences i spectral diagnostics and non lte modelling
arXiv: Solar and Stellar Astrophysics, 2010Co-Authors: N Labrosse, B Schmieder, S. Gunár, P. Heinzel, J.-c. Vial, S. Parenti, Therese A Kucera, G. KilperAbstract:This review paper outlines background information and covers recent advances made via the analysis of spectra and images of Prominence plasma and the increased sophistication of non-LTE (ie when there is a departure from Local Thermodynamic Equilibrium) radiative transfer models. We first describe the spectral inversion techniques that have been used to infer the plasma parameters important for the general properties of the Prominence plasma in both its cool core and the hotter Prominence-corona transition region. We also review studies devoted to the observation of bulk motions of the Prominence plasma and to the determination of Prominence mass. However, a simple inversion of spectroscopic data usually fails when the lines become optically thick at certain wavelengths. Therefore, complex non-LTE models become necessary. We thus present the basics of non-LTE radiative transfer theory and the associated multi-level radiative transfer problems. The main results of one- and two-dimensional models of the Prominences and their fine-structures are presented. We then discuss the energy balance in various Prominence models. Finally, we outline the outstanding observational and theoretical questions, and the directions for future progress in our understanding of solar Prominences.
Weiqun Gan - One of the best experts on this subject based on the ideXlab platform.
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solar magnetized tornadoes rotational motion in a tornado like Prominence
The Astrophysical Journal, 2014Co-Authors: P Gomory, Astrid M Veronig, Manuela Temmer, Tongjiang Wang, Kamalam Vanninathan, Weiqun GanAbstract:Su et al. proposed a new explanation for filament formation and eruption, where filament barbs are rotating magnetic structures driven by underlying vortices on the surface. Such structures have been noticed as tornado-like Prominences when they appear above the limb. They may play a key role as the source of plasma and twist in filaments. However, no observations have successfully distinguished rotational motion of the magnetic structures in tornado-like Prominences from other motions such as oscillation and counter-streaming plasma flows. Here we report evidence of rotational motions in a tornado-like Prominence. The spectroscopic observations in two coronal lines were obtained from a specifically designed Hinode/EIS observing program. The data revealed the existence of both cold and million-degree-hot plasma in the Prominence leg, supporting the so-called Prominence-corona transition region. The opposite velocities at the two sides of the Prominence and their persistent time evolution, together with the periodic motions evident in SDO/AIA dark structures, indicate a rotational motion of both cold and hot plasma with a speed of similar to 5 km s(-1).
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solar magnetized tornadoes rotational motion in a tornado like Prominence
arXiv: Solar and Stellar Astrophysics, 2013Co-Authors: P Gomory, Astrid M Veronig, Manuela Temmer, Tongjiang Wang, Kamalam Vanninathan, Weiqun GanAbstract:Su et al. 2012 proposed a new explanation for filament formation and eruption, where filament barbs are rotating magnetic structures driven by underlying vortices on the surface. Such structures have been noticed as tornado-like Prominences when they appear above the limb. They may play a key role as the source of plasma and twist in filaments. However, no observations have successfully distinguished rotational motion of the magnetic structures in tornado-like Prominences from other motions such as oscillation and counter-streaming plasma flows. Here we report evidence of rotational motions in a tornado-like Prominence. The spectroscopic observations in two coronal lines were obtained from a specifically designed Hinode/EIS observing program. The data revealed the existence of both cold and million-degree-hot plasma in the Prominence leg, supporting the so-called "the Prominence-corona transition region". The opposite velocities at the two sides of the Prominence and their persistent time evolution, together with the periodic motions evident in SDO/AIA dark structures, indicate a rotational motion of both cold and hot plasma with a speed of $\sim$5 km s$^{-1}$.
