Search Publications
Reconstruction of total solar irradiance 1974-2009
Jaffe, A. H.; Krivova, N. A.; Solanki, S. +4 more
Context. The study of variations in total solar irradiance (TSI) is important for understanding how the Sun affects the Earth's climate.
Aims: Full-disk continuum images and magnetograms are now available for three full solar cycles. We investigate how modelled TSI compares with direct observations by building a consistent modelled TSI datase…
An active region filament studied simultaneously in the chromosphere and photosphere. I. Magnetic structure
Martínez Pillet, V.; Centeno, R.; Kuckein, C.
Aims: A thorough multiwavelength, multiheight study of the vector magnetic field in a compact active region filament (NOAA 10781) on 2005 July 3 and 5 is presented. We suggest an evolutionary scenario for this filament.
Methods: Two different inversion codes were used to analyze the full Stokes vectors acquired with the Tenerife Infrared…
Observations and simulations of longitudinal oscillations of an active region prominence
Chen, P. F.; Zhang, Q. M.; Xia, C. +1 more
Context. Filament longitudinal oscillations have been observed in Hα observations of the solar disk.
Aims: We intend to find an example of the longitudinal oscillations of a prominence, where the magnetic dip can be seen directly, and examine the restoring force of this type of oscillations.
Methods: We carry out a multiwavelength data a…
X-ray and ultraviolet investigation into the magnetic connectivity of a solar flare
Aulanier, G.; Pariat, E.; Vilmer, N. +1 more
We investigate the X-ray and UV emission detected by RHESSI and TRACE in the context of a solar flare on the 16th November 2002 with the goal of better understanding the evolution of the flare. We analysed the characteristics of the X-ray emission in the 12-25 and 25-50 keV energy range while we looked at the UV emission at 1600 Å . The flare appe…
Are the strengths of solar cycles determined by converging flows towards the activity belts?
Schüssler, M.; Cameron, R. H.
It is proposed that the observed near-surface inflows towards the active regions and sunspot zones provide a nonlinear feedback mechanism that limits the amplitude of a Babcock-Leighton-type solar dynamo and determines the variation of the cycle strength. This hypothesis is tested with surface flux transport simulations including converging latitu…
Basal magnetic flux and the local solar dynamo
Stenflo, J. O.
The average unsigned magnetic flux density in magnetograms of the quiet Sun is generally dominated by instrumental noise. Due to the entirely different scaling behavior of the noise and the solar magnetic pattern it has been possible to determine the standard deviation of the Gaussian noise distribution and remove the noise contribution from the a…
Coronal hole boundaries evolution at small scales. III. EIS and SUMER views
Doyle, J. G.; Madjarska, M. S.; Huang, Z. +1 more
Context. We report on the plasma properties of small-scale transient events identified in the quiet Sun, coronal holes and their boundaries.
Aims: We aim at deriving the physical characteristics of events that were identified as small-scale transient brightenings in XRT images.
Methods: We used spectroscopic co-observations from SUMER/So…
The interplanetary magnetic structure that guides solar relativistic particles
Klein, K. -L.; Démoulin, P.; Dasso, S. +1 more
Context. Relating in-situ measurements of relativistic solar particles to their parent activity in the corona requires understanding the magnetic structures that guide them from their acceleration site to the Earth. Relativistic particle events are observed at times of high solar activity, when transient magnetic structures such as interplanetary …
The quasi-biennial periodicity (QBP) in velocity and intensity helioseismic observations. The seismic QBP over solar cycle 23
García, R. A.; Roth, M.; Finsterle, W. +4 more
Aims: We looked for signatures of quasi-biennial periodicity (QBP) over different phases of solar cycle by means of acoustic modes of oscillation. Low-degree p-mode frequencies are shown to be sensitive to changes in magnetic activity due to the global dynamo. Recently there has been reported evidence of two-year variations in p-mode frequenc…
Frequency drifts of 3-min oscillations in microwave and EUV emission above sunspots
Nakariakov, V. M.; Shibasaki, K.; Yan, Y. +3 more
Aims: We analysed 3-min oscillations of microwave and extreme ultraviolet (EUV) emission generated at different heights of a sunspot atmosphere, studied the amplitude and frequency modulation of the oscillations, and its relationship with the variation of the spatial structure of the oscillations.
Methods: High-resolution data obtained w…