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Large-scale waves in the solar corona: The continuing debate
Warmuth, Alexander
Ten years after the first observation of large-scale wave-like coronal disturbances with the EIT instrument aboard SOHO, the most crucial questions concerning these “EIT waves” are still being debated controversially - what is their actual physical nature, and how are they launched? Possible explanations include MHD waves or shocks, launched by fl…
Turbulence, complexity, and solar flares
Gallagher, Peter T.; McAteer, R. T. James; Conlon, Paul A.
The issue of predicting solar flares is one of the most fundamental in physics, addressing issues of plasma physics, high-energy physics, and modelling of complex systems. It also poses societal consequences, with our ever-increasing need for accurate space weather forecasts. Solar flares arise naturally as a competition between an input (flux eme…
Characterization of the slow wind in the outer corona
Antonucci, Ester; Riley, Pete; Linker, Jon A. +3 more
The study concerns the streamer belt observed at high spectral resolution during the minimum of solar cycle 23 with the Ultraviolet Coronagraph Spectrometer (UVCS) onboard SOHO. On the basis of a spectroscopic analysis of the O VI doublet, the solar wind plasma parameters are inferred in the extended corona. The analysis accounts for the coronal m…
Total solar irradiance absolute level from DIARAD/SOVIM on the International Space Station
Mekaoui, Sabri; Dewitte, Steven; Conscience, Christian +1 more
Current measurements from DIARAD/VIRGO, PMO6V/VIRGO and ACRIM3 radiometers are of the same order of magnitude, but differ from TIM/SORCE by about 4.5 W m -2. This difference is higher than the sum of the claimed individual absolute uncertainties of the instruments. In this context, the SOLAR payload on the International Space Station em…
Solar wind origins in coronal holes and in the quiet Sun
Tu, C. -Y.; Marsch, E.; Tian, H. +1 more
Coronal hole (CH) and the quiet Sun (QS) are considered to account for sources of fast and slow solar wind streams, respectively. The differences between the solar wind streams flowing out from the CH and the QS are thought to be related with different plasma generation and acceleration mechanisms in the respective source regions. Here we review r…
A morphological study of CMEs using wavelet analysis
Raga, A. C.; Blanco-Cano, X.; González-Gómez, D. I.
The principal objective of this study is to analyze structures of Coronal Mass Ejections (CMEs) using a wavelet technique. We use data measured with the SOHO/LASCO coronographs C2-C3, EIT and STEREO COR1A-B, COR2A-B. We have found that different structures show up in a CME at different spatial scales of wavelets. We also study the orientation of t…
On the nature of coronal loops above the quiet sun network
Peter, H.; Zacharias, P.; Bingert, S. +1 more
The structure and dynamics of a box in a stellar corona can be modeled employing a 3D MHD model for different levels of magnetic activity. Depending on the magnetic flux through the surface the nature of the resulting coronal structures can be quite different. We investigate a model of an active region for two sunspots surrounded by magnetic field…