Search Publications
Photospheric flux cancellation and associated flux rope formation and eruption
Green, L. M.; Kliem, B.; Wallace, A. J.
Aims: We study an evolving bipolar active region that exhibits flux cancellation at the internal polarity inversion line, the formation of a soft X-ray sigmoid along the inversion line and a coronal mass ejection. The aim is to investigate the quantity of flux cancellation that is involved in flux rope formation in the time period leading up …
SDO AIA and Hinode EIS observations of "warm" loops
Mason, H. E.; Del Zanna, G.; O'Dwyer, B.
We present simultaneous observations of active region "warm" (1 MK) loops using the Solar Dynamics Observatory (SDO) Atmospheric Imaging Assembly (AIA) and Hinode EUV Imaging Spectrometer (EIS). Sample EIS spectra for a loop footpoint and a lop leg region are presented, and are used to describe the spectral lines which contribute to the six AIA EU…
A single picture for solar coronal outflows and radio noise storms
Aulanier, G.; Klein, K. -L.; Del Zanna, G. +1 more
We propose a unified interpretation for persistent coronal outflows and metric radio noise storms, two phenomena typically observed in association with quiescent solar active regions. Our interpretation is based on multi-wavelength observations of two such regions as they crossed the meridian in May and July 2007. For both regions, we observe a pe…
Inferring the magnetic field vector in the quiet Sun. I. Photon noise and selection criteria
Borrero, J. M.; Kobel, P.
In the past, spectropolarimetric data from Hinode/SP were employed to infer the distribution of the magnetic field vector in the quiet Sun. While some authors found predominantly horizontal magnetic fields, others favor an isotropic distribution. We investigate whether it is actually possible to accurately retrieve the magnetic field vector in reg…
MHD wave transmission in the Sun's atmosphere
Berrilli, F.; Del Moro, D.; Stangalini, M. +1 more
Magnetohydrodynamics (MHD) wave propagation inside the Sun's atmosphere is closely related to the magnetic field topology. For example, magnetic fields are able to lower the cutoff frequency for acoustic waves, thus allowing the propagation of waves that would otherwise be trapped below the photosphere into the upper atmosphere. In addition, MHD w…
The 22 May 2007 B-class flare: new insights from Hinode observations
Mason, H. E.; Del Zanna, G.; Bradshaw, S. J. +2 more
We present multi-wavelength observations of a small B-class flare which occurred on the Sun on 2007 May 22. The observations include data from Hinode, GOES, TRACE and the Nobeyama Radioheliograph. We obtained spatially and spectrally-resolved information from the Hinode EUV Imaging Spectrometer (EIS) during this event. The temporal and temperature…
Asymmetries of the Stokes V profiles observed by HINODE SOT/SP in the quiet Sun
Sánchez Almeida, J.; Viticchié, B.
Aims: A recent analysis of polarization measurements of HINODE SOT/SP in the quiet Sun pointed out very complex shapes of Stokes V profiles. Here we present the first classification of the SOT/SP circular polarization measurements with the aim of highlighting exhaustively the whole variety of Stokes V shapes emerging from the quiet Sun.
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Continuous upflows and sporadic downflows observed in active regions
Peter, H.; Solanki, S. K.; Curdt, W. +1 more
Aims: We present a study of the temporal evolution of coronal loops in active regions and its implications for the dynamics in coronal loops.
Methods: We analyzed images of the Atmospheric Imaging Assembly (AIA) on the Solar Dynamics Observatory (SDO) at multiple temperatures to detect apparent motions in the coronal loops.
Results:…
Dynamics and plasma properties of an X-ray jet from SUMER, EIS, XRT, and EUVI A & B simultaneous observations
Madjarska, M. S.
Context. Small-scale transient phenomena in the quiet Sun are believed to play an important role in coronal heating and solar wind generation. One of them, called “X-ray jet”, is the subject of our study.
Aims: We intend to investigate the dynamics, evolution, and physical properties of this phenomenon.
Methods: We combine multi-instrume…
Advection and dispersal of small magnetic elements in the very quiet Sun
Asensio Ramos, A.; Martínez González, M. J.; Manso Sainz, R.
We track small magnetic structures on very quiet regions (internetwork) of the Sun. We follow the footpoints of small-scale magnetic loops that appear on the photosphere at granular scales using spectropolarimetric and magnetographic data obtained with Hinode. We find two different regimes for their wanderings. Within granules (where they appear),…