Search Publications
Excitation of kink oscillations of coronal loops: statistical study
Zimovets, I. V.; Nakariakov, V. M.
Context. Solar flares are often accompanied by kink (transverse) oscillations of coronal loops. Despite intensive study of these oscillations in recent years, the mechanisms that excite them are still not known.
Aims: We aim to clarify the excitation mechanisms for these kink oscillations of coronal loops.
Methods: We analysed 58 kink-os…
Properties of solar energetic particle events inferred from their associated radio emission
Valtonen, E.; Hillaris, A.; Malandraki, O. +6 more
Aims: We study selected properties of solar energetic particle (SEP) events as inferred from their associated radio emissions.
Methods: We used a catalogue of 115 SEP events, which consists of entries of proton intensity enhancements at one AU, with complete coverage over solar cycle 23 based on high-energy (~68 MeV) protons from SOHO/ER…
Seismic sensitivity to sub-surface solar activity from 18 yr of GOLF/SoHO observations
García, R. A.; Turck-Chièze, S.; Salabert, D.
Solar activity has significantly changed over the last two Schwabe cycles. After a long and deep minimum at the end of Cycle 23, the weaker activity of Cycle 24 contrasts with the previous cycles. In this work, the response of the solar acoustic oscillations to solar activity is used in order to provide insights into the structural and magnetic ch…
Spatially resolved vertical vorticity in solar supergranulation using helioseismology and local correlation tracking
Birch, A. C.; Gizon, L.; Langfellner, J.
Flow vorticity is a fundamental property of turbulent convection in rotating systems. Solar supergranules exhibit a preferred sense of rotation, which depends on the hemisphere. This is due to the Coriolis force acting on the diverging horizontal flows. We aim to spatially resolve the vertical flow vorticity of the average supergranule at differen…
Recurrent flares in active region NOAA 11283
Romoli, M.; Vecchio, A.; Pietropaolo, E. +21 more
Context. Flares and coronal mass ejections (CMEs) are solar phenomena that are not yet fully understood. Several investigations have been performed to single out their related physical parameters that can be used as indices of the magnetic complexity leading to their occurrence.
Aims: In order to shed light on the occurrence of recurrent flar…
The role of the Fraunhofer lines in solar brightness variability
Solanki, S. K.; Shapiro, A. I.; Tagirov, R. V. +2 more
Context. The solar brightness varies on timescales from minutes to decades. A clear identification of the physical processes behind such variations is needed for developing and improving physics-based models of solar brightness variability and reconstructing solar brightness in the past. This is, in turn, important for better understanding the sol…
Hydrogen Ly-α and Ly-β full Sun line profiles observed with SUMER/SOHO (1996-2009)
Vial, J. -C.; Wilhelm, K.; Curdt, W. +2 more
Context. Accurate hydrogen spectra emitted by the entire solar disc in the Ly-α and Ly-βlines are valuable for deriving the distribution and the behaviour of atomic hydrogen in the heliosphere, for understanding the UV emissions of solar type stars better, and finally for estimating the solar energy input that mainly initiates the chemical process…
An automated classification approach to ranking photospheric proxies of magnetic energy build-up
McAteer, R. T. J.; Al-Ghraibah, A.; Boucheron, L. E.
Aims: We study the photospheric magnetic field of ~2000 active regions over solar cycle 23 to search for parameters that may be indicative of energy build-up and its subsequent release as a solar flare in the corona.
Methods: We extract three sets of parameters: (1) snapshots in space and time: total flux, magnetic gradients, and neutral…
Estimate of the erosion rate from H2O mass-loss measurements from SWAN/SOHO in previous perihelions of comet 67P/Churyumov-Gerasimenko and connection with observed rotation rate variations
Bertaux, Jean-Loup
Context. The SWAN Lyman α photometer onboard SOHO monitored the hydrogen cloud around comet 67P/Churyumov-Gerasimenko (67P) postperihelion at the three last perihelions in 1996, 2002, and 2009.
Aims: Combining the SWAN results with some new Rosetta data allows estimating the erosion rate of the comet, quantified by the thickness of a layer th…
Proton intensity spectra during the solar energetic particle events of May 17, 2012 and January 6, 2014
Dresing, N.; Heber, B.; Kühl, P. +4 more
Context. Ground-level enhancements (GLEs) are solar energetic particle events that show a significant intensity increase at energies that can be measured by neutron monitors. The most recent GLE-like events were recorded on May 17, 2012 and January 6, 2014. They were also measured by sophisticated instrumentation in space such as PAMELA and the El…