Search Publications
Analysis and modelling of recurrent solar flares observed with Hinode/EIS on March 9, 2012
Mason, H. E.; Del Zanna, G.; Pariat, E. +4 more
Three homologous C-class flares and one last M-class flare were observed by both the Solar Dynamics Observatory (SDO) and the Hinode EUV Imaging Spectrometer (EIS) in the AR 11429 on March 9, 2012. All the recurrent flares occurred within a short interval of time (less than 4 h), showed very similar plasma morphology and were all confined, until t…
Excitation and evolution of vertically polarised transverse loop oscillations by coronal rain
Kohutova, P.; Verwichte, E.
Context. Coronal rain is composed of cool dense blobs that form in solar coronal loops and are a manifestation of catastrophic cooling linked to thermal instability. The nature and excitation of oscillations associated with coronal rain is not well understood.
Aims: We consider observations of coronal rain in a bid to elucidate the excitation…
Multi-instrument observations of a failed flare eruption associated with MHD waves in a loop bundle
Del Zanna, G.; Nakariakov, V. M.; Polito, V. +1 more
Context. We present observations of a B7.9-class flare that occurred on the 24th January, 2015, using the Atmospheric Imaging Assembly (AIA) of the Solar Dynamics Observatory (SDO), the EUV Imaging Spectrometer (EIS) and the X-Ray Telescope of Hinode. The flare triggers the eruption of a dense cool plasma blob as seen in AIA 171 Å, which is unable…
A distinct magnetic property of the inner penumbral boundary. II. Formation of a penumbra at the expense of a pore
Jurčák, J.; Bello González, N.; Schlichenmaier, R. +1 more
Context. We recently presented evidence that stable umbra-penumbra boundaries are characterised by a distinct canonical value of the vertical component of the magnetic field, Bstablever. In order to trigger the formation of a penumbra, large inclinations in the magnetic field are necessary. In sunspots, the penumbra develops …
Kinematics of coronal rain in a transversely oscillating loop: Ponderomotive force and rain-excited oscillations
Kohutova, P.; Verwichte, E.; Neukirch, T. +2 more
Context. Coronal rain is composed of cool dense blobs that form in solar coronal loops and are a manifestation of catastrophic cooling linked to thermal instability. Once formed, rain falls towards the solar surface at sub-ballistic speeds, which is not well understood. Pressure forces seem to be the prime candidate to explain this. In many observ…
Reconstruction of a helical prominence in 3D from IRIS spectra and images
Schmieder, B.; Labrosse, N.; López Ariste, A. +3 more
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 …
Cool and hot emission in a recurring active region jet
Del Zanna, Giulio; Mulay, Sargam M.; Mason, Helen
Aims: We present a thorough investigation of the cool and hot temperature components in four recurring active region jets observed on July 10, 2015 using the Atmospheric Imaging Assembly (AIA), X-ray Telescope (XRT), and Interface Region Imaging Spectrograph (IRIS) instruments.
Methods: A differential emission measure (DEM) analysis was …
Vertical magnetic field gradient in the photospheric layers of sunspots
Joshi, Jayant; Lagg, Andreas; Hirzberger, Johann +2 more
Aims: We investigate the vertical gradient of the magnetic field of sunspots in the photospheric layer.
Methods: Independent observations were obtained with the Solar Optical Telescope/Spectropolarimeter (SOT/SP) on board the Hinode spacecraft and with the Tenrife Infrared Polarimeter-2 (TIP-2) mounted at the German Vacuum Tower Telescop…
Normal and counter Evershed flows in the photospheric penumbra of a sunspot. SPINOR 2D inversions of Hinode-SOT/SP observations
Solanki, S. K.; Lagg, A.; Jurčák, J. +2 more
Context. The Evershed effect, a nearly horizontal outflow of material seen in the penumbrae of sunspots in the photospheric layers, is a common characteristic of well-developed penumbrae, but is still not well understood. Even less is known about photospheric horizontal inflows in the penumbra, also known as counter Evershed flows.
Aims: Here…
Magnetic topological analysis of coronal bright points
Madjarska, M. S.; Huang, Z.; Wiegelmann, T. +2 more
Context. We report on the first of a series of studies on coronal bright points which investigate the physical mechanism that generates these phenomena.
Aims: The aim of this paper is to understand the magnetic-field structure that hosts the bright points.
Methods: We use longitudinal magnetograms taken by the Solar Optical Telescope wit…