Multi-source connectivity as the driver of solar wind variability in the heliosphere.

The ambient solar wind that fills the heliosphere originates from multiple sources in the solar corona and is highly structured. It is often described as high-speed, relatively homogeneous, plasma streams from coronal holes and slow-speed, highly variable, streams whose source regions are under debate. A key goal of ESA/NASA's Solar Orbiter mission is to identify solar wind sources and understand what drives the complexity seen in the heliosphere.

Definition of the Spatial Propagator and Implications for Magnetic Field Properties.

We present a theoretical framework to analyze the 3D coronal vector magnetic-field structure. We assume that the vector magnetic field exists and is smooth. We introduce a generalized connectivity phase space associated with the vector magnetic field in which the basic elements are the and its linearized variation: the .

Apparent and Intrinsic Evolution of Active Region Upflows.

Unlabelled: We analyze the evolution of Fe xii coronal plasma upflows from the edges of ten active regions (ARs) as they cross the solar disk using the (EIS) to do this. Confirming the results of Démoulin ( , 341, 2013), we find that for each AR there is an observed long-term evolution of the upflows. This evolution is largely due to the solar rotation that progressively changes the viewpoint of dominantly stationary upflows.

Strong coronal channelling and interplanetary evolution of a solar storm up to Earth and Mars.

The severe geomagnetic effects of solar storms or coronal mass ejections (CMEs) are to a large degree determined by their propagation direction with respect to Earth. There is a lack of understanding of the processes that determine their non-radial propagation. Here we present a synthesis of data from seven different space missions of a fast CME, which originated in an active region near the disk centre and, hence, a significant geomagnetic impact was forecasted.

Our changing atmosphere: evidence based on long-term infrared solar observations at the Jungfraujoch since 1950.

The Institute of Astrophysics of the University of Liège has been present at the High Altitude Research Station Jungfraujoch, Switzerland, since the late 1940s, to perform spectrometric solar observations under dry and weakly polluted high-mountain conditions. Several solar atlases of photometric quality, extending altogether from the near-ultra-violet to the middle-infrared, were produced between 1956 and 1994, first with grating spectrometers then with Fourier transform instruments. During the early 1970s, scientific concerns emerged about atmospheric composition changes likely to set in as a consequence of the growing usage of nitrogen-containing agricultural fertilisers and the industrial production of chlorine-bearing compounds such as the chlorofluorocarbons and hydro-chlorofluorocarbons.