Search Publications
The magnetic field in the solar atmosphere
Solanki, Sami K.; Wiegelmann, Thomas; Thalmann, Julia K.
This publication provides an overview of magnetic fields in the solar atmosphere with the focus lying on the corona. The solar magnetic field couples the solar interior with the visible surface of the Sun and with its atmosphere. It is also responsible for all solar activity in its numerous manifestations. Thus, dynamic phenomena such as coronal m…
Solar magnetic fields as revealed by Stokes polarimetry
Stenflo, J. O.
Observational astrophysics started when spectroscopy could be applied to astronomy. Similarly, observational work on stellar magnetic fields became possible with the application of spectro-polarimetry. In recent decades there have been dramatic advances in the observational tools for spectro-polarimetry. The four Stokes parameters that provide a c…
Solar flares at submillimeter wavelengths
Krucker, Säm; Kretzschmar, M.; Klein, K. -L. +10 more
We discuss the implications of the first systematic observations of solar flares at submillimeter wavelengths, defined here as observing wavelengths shorter than 3 mm (frequencies higher than 0.1 THz). The events observed thus far show that this wave band requires a new understanding of high-energy processes in solar flares. Several events, includ…
Morphology, dynamics and plasma parameters of plumes and inter-plume regions in solar coronal holes
Llebaria, A.; Auchère, F.; Feng, L. +12 more
Coronal plumes, which extend from solar coronal holes (CH) into the high corona and—possibly—into the solar wind (SW), can now continuously be studied with modern telescopes and spectrometers on spacecraft, in addition to investigations from the ground, in particular, during total eclipses. Despite the large amount of data available on these promi…
The quest for the solar g modes
Baudin, F.; García, R. A.; Provost, J. +18 more
Solar gravity modes (or g modes)—oscillations of the solar interior on which buoyancy acts as the restoring force—have the potential to provide unprecedented inference on the structure and dynamics of the solar core, inference that is not possible with the well-observed acoustic modes (or p modes). The relative high amplitude of the g-mode eigenfu…
Sixty-five years of solar radioastronomy: flares, coronal mass ejections and Sun Earth connection
Vilmer, Nicole; Pick, Monique
This paper will review the input of 65 years of radio observations to our understanding of solar and solar terrestrial physics. It is focussed on the radio observations of phenomena linked to solar activity in the period going from the first discovery of the radio emissions to present days. We shall present first an overview of solar radio physics…
Asteroseismology and interferometry
Quirrenbach, A.; Eggenberger, P.; Thompson, M. J. +22 more
Asteroseismology provides us with a unique opportunity to improve our understanding of stellar structure and evolution. Recent developments, including the first systematic studies of solar-like pulsators, have boosted the impact of this field of research within astrophysics and have led to a significant increase in the size of the research communi…
Minor ions in the solar wind
Bochsler, Peter
Ions heavier than 4He are treated as “minors” in the solar wind. This is justified for many applications since minor ions have no significant influence on the dynamics of the interplanetary plasma. However, minor ions carry information on many aspects of the formation, on the acceleration and on the transfer of solar plasma from the cor…
Ultraviolet spectroscopy of the extended solar corona
Kohl, John L.; Noci, Giancarlo; Cranmer, Steven R. +1 more
The first observations of ultraviolet spectral line profiles and intensities from the extended solar corona (i.e., more than 1.5 solar radii from Sun-center) were obtained on 13 April 1979 when a rocket-borne ultraviolet coronagraph spectrometer of the Harvard-Smithsonian Center for Astrophysics made direct measurements of proton kinetic temperatu…
Solar radiative output and its variability: evidence and mechanisms
Fröhlich, Claus; Lean, Judith
Electromagnetic radiation from the Sun is Earth’s primary energy source. Space-based radiometric measurements in the past two decades have begun to establish the nature, magnitude and origins of its variability. An 11-year cycle with peak-to-peak amplitude of order 0.1 % is now well established in recent total solar irradiance observations, as are…