Stray light testing of WISPR baffle development model

Solar Probe Plus (SPP) is a NASA mission developed to visit and study the sun closer than ever before. SPP is designed to orbit as close as 7 million km (9.86 solar radii) from Sun center. One of its instruments: WISPR (Wide-Field Imager for Solar Probe Plus) will be the first ‘local’ imager to provide the relation between the large-scale corona and the in-situ measurements.The Centre Spatial de Liège in Belgium (CSL) owns a stray light test facility for In Field and Out of Field of View stray light measurements. This facility is updated to realize a stray light test on the WISPR Development Model (DM).WISP

Observations of the White Light Corona from Solar Orbiter and Solar Probe Plus

The SoloHI instrument on Solar Orbiter and the WISPR instrument on Solar Probe+ will make white light coronagraphic images of the corona as the two spacecraft orbit the Sun. The minimum perihelia for Solar Orbiter is about 60 Rsun and for SP+ is 9.5 Rsun. The wide field of view of the WISPR instrument (about 105 degrees radially) corresponds to viewing the corona from 2.2 Rsun to 20 Rsun. Thus the entire Thomson hemisphere is contained within the telescope’s field and we need to think of the instrument as being a traditional remote sensing instrument and then transitioning to a local in-situ instrument. The local behavior derives from the fact that the maximum Thomson scattering will favor the electron plasma close to the spacecraft - exactly what the in-situ instruments will be sampling. SoloHI and WISPR will also observe scattered light from dust in the inner heliosphere, which will be an entirely new spatial regime for dust observations from a coronagraph, which we assume to arise from dust in the general neighborhood of about half way between the observer and the Sun. As the dust grains approach the Sun, they evaporate and do not contribute to the scattering. A dust free zone has been postulated to exist somewhere inside of 5 Rsun where all dust is evaporated, but this has never been observed. The radial position where the evaporation occurs will depend on the precise molecular composition of the individual grains. The orbital plane of Solar Orbiter will gradually increase up to about 35 degrees, enabling a very different view through the zodiacal dust cloud to test the models generated from in-ecliptic observations. In this paper we will explore some of the issues associated with the observation of the dust and will present a simple model to explore the sensitivity of the instrument to observe such evaporations

Nova razmerja: razstava ob Tednu Univerze

Sodobna grafika zajema iz postopkov stare mehanične, ročne tradicije na eni in iz digitaliziranih novomedijskih strojnih možnostmi na drugi strani. Med tema dvema paradigmama obstaja stalen latenten spor o pomenu, vrednotah in smotru sodobne grafike. Nekateri avtorji trdo zagovarjajo svoja stališča in se strastno udeležujejo mnenjskih debat, drugi pa vzamejo iz vsakega področja tisto, kar jim najbolj ustreza in mirno razvijajo svojo umetnost naprej. Med te slednje sodi Zora Stančič, ki na tej razstavi razgrinja kratek pregled različnih faz svojega grafičnega delovanja. Doma in v svetu uveljavljena avtorica je od lanskega leta zunanja sodelavka Oddelka za likovno pedagogiko PeF UL

Near-Sun observations of an F-corona decrease and K-corona fine structure

Remote observations of the solar photospheric light scattered by electrons (the K-corona) and dust (the F-corona or zodiacal light) have been made from the ground during eclipses1 and from space at distances as small as 0.3 astronomical units2–5 to the Sun. Previous observations6–8 of dust scattering have not confirmed the existence of the theoretically predicted dust-free zone near the Sun9–11. The transient nature of the corona has been well characterized for large events, but questions still remain (for example, about the initiation of the corona12 and the production of solar energetic particles13) and for small events even its structure is uncertain14. Here we report imaging of the solar corona15 during the first two perihelion passes (0.16–0.25 astronomical units) of the Parker Solar Probe spacecraft13, each lasting ten days. The view from these distances is qualitatively similar to the historical views from ground and space, but there are some notable differences. At short elongations, we observe a decrease in the intensity of the F-coronal intensity, which is suggestive of the long-sought dust free zone9–11. We also resolve the fine-scale plasma structure of very small eruptions, which are frequently ejected from the Sun. These take two forms: the frequently observed magnetic flux ropes12,16 and the predicted, but not yet observed, magnetic islands17,18 arising from the tearing-mode instability in the current sheet. Our observations of the coronal streamer evolution confirm the large-scale topology of the solar corona, but also reveal that, as recently predicted19, streamers are composed of yet smaller substreamers channelling continual density fluctuations at all visible scales. © 2019, The Author(s), under exclusive licence to Springer Nature Limited