Search Publications
Reconstruction of solar total irradiance since 1700 from the surface magnetic flux
Solanki, S. K.; Krivova, N. A.; Balmaceda, L.
Context: Total solar irradiance changes by about 0.1% between solar activity maximum and minimum. Accurate measurements of this quantity are only available since 1978 and do not provide information on longer-term secular trends.
Aims: In order to reliably evaluate the Sun's role in recent global climate change, longer time series are, however,…
The Hα surges and EUV jets from magnetic flux emergences and cancellations
Yang, L. H.; Li, K. J.; Jiang, Y. C. +2 more
We analyzed multi-wavelength observations of three surges with a recurrent period of about 70 min in Hα, EUV, and soft X-ray, which occurred in the quiet-sun region on 2000 November 3. These homologous surges were associated with small flares at the same base, but their exact footpoints were spatially separated from the flare. Each surge consisted…
X-ray precursors to flares and filament eruptions
Mason, H. E.; Dennis, B. R.; Tripathi, D. +1 more
Aims:To study preflare X-ray brightenings as diagnostics of the destabilisation of flare-associated erupting filaments/prominences.
Methods: We combine new observations from the Transition Region and Coronal Explorer (TRACE) and the Reuven Ramaty High Energy Solar Spectroscopic Imager (RHESSI), as well as revisit events reported in the literat…
Properties of sunspots in cycle 23. I. Dependence of brightness on sunspot size and cycle phase
Solanki, S. K.; Martínez Pillet, V.; Krivova, N. A. +1 more
Aims:In this paper we investigate the dependence of umbral core brightness, as well as the mean umbral and penumbral brightness on the phase of the solar cycle and on the size of the sunspot.
Methods: Albregtsen & Maltby (1978, Nature, 274, 41) reported an increase in umbral core brightness from the early to the late phase of solar cycle f…
Spectrophotometric analysis of Ellerman bombs in the Ca II, Hα, and UV range
Schmieder, B.; Pariat, E.; Wang, S. +4 more
Context: Even if Ellerman bombs have been observed in the Hα line within emerging magnetic flux regions since the early 20th century, their origin and the mechanisms that lead to their formation have been strongly debated. Recently, new arguments in favor of chromospheric magnetic reconnection have been advanced. Ellerman bombs seem to be the sign…
Large amplitude oscillatory motion along a solar filament
Veronig, A. M.; Vršnak, B.; Thalmann, J. K. +1 more
Context: Large amplitude oscillations of solar filaments is a phenomenon that has been known for more than half a century. Recently, a new mode of oscillations, characterized by periodical plasma motions along the filament axis, was discovered.
Aims: We analyze such an event, recorded on 23 January 2002 in Big Bear Solar Observatory Hα filterg…
Rapid rotation of a sunspot associated with flares
Yan, X. L.; Qu, Z. Q.
Context: Active region NOAA 10424 observed on August 5, 2003 is studied in detail by using TRACE, SOHO/MDI, BBSO Hα monograph, and GOES data. This investigation focuses on the sunspot rotation and its relation with the eruptive phenomena by analyzing the magnetic configuration that the rotation results in.
Aims: It is shown that there is a clo…
Stationary parts of an EIT and Moreton wave: a topological model
Aulanier, G.; Hochedez, J. -F.; Delannée, C.
Context: EIT and Moreton waves came into focus in 1997, when a propagating disturbance on a large area of the solar disc was discovered. The process generating the EIT and Moreton waves has been frequently discussed.
Aims: On May 2, 1998, a halo CME was observed related to an EIT wave, a Moreton wave, a X1 flare, radio emission sources, and di…
Comparing different approaches to model the rotational modulation of the Sun as a star
Lanza, A. F.; Rodonò, M.; Bonomo, A. S.
Context: The space missions MOST, COROT and Kepler are going to provide us with high-precision optical photometry of solar-like stars with time series extending from tens of days to several years. They can be modelled to obtain information on stellar magnetic activity by fitting the rotational modulation of the stellar flux produced by the brightn…
Nonlinear force-free models for the solar corona. I. Two active regions with very different structure
Régnier, S.; Priest, E. R.
Context: With the development of new instrumentation providing measurements of solar photospheric vector magnetic fields, we need to develop our understanding of the effects of current density on coronal magnetic field configurations.
Aims: The object is to understand the diverse and complex nature of coronal magnetic fields in active regions …