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.

Solar autocalibrating XUV-IR spectrometer system (SOLACER) for the measurement of solar spectral irradiance.

The accurate measurement of solar spectral irradiance (SSI) from space is challenging because it requires a system that can reliably exclude the impact of degradation on the instruments for the full duration of a long-term mission. The new Autocalibrating XUV-IR Spectrometer System (SOLACER) presented here meets this requirement. It is a compact and moderate-cost instrument that allows repeated onboard calibration of the spectrometers (SPs) providing SSI data of significantly increased accuracy.