SPICE connection mosaics to link the Sun’s surface and the heliosphere

¹ Institut National Polytechnique de Grenoble, 38000 Grenoble, France
² Southwest Research Institute, Boulder, CO, 80302, USA
³ Department of Aerospace Engineering Sciences, University of Colorado Boulder, Boulder, CO, USA
e-mail: tania.varesano@colorado.edu
⁴ NASA Goddard Space Flight Center, Greenbelt, MD, USA
⁵ DAMTP, Centre for Mathematical Sciences, Wilberforce Road, Cambridge, CB3 0WA, UK
⁶ Université Paris-Saclay, CNRS, Institut d’Astrophysique Spatiale, 91405 Orsay, France
⁷ RAL Space, UKRI STFC Rutherford Appleton Laboratory, Didcot, UK
⁸ Institute of Theoretical Astrophysics, University of Oslo, Oslo, Norway
⁹ Max-Planck-Institut fur Sonnensystemforschung, Gottingen, Germany
¹⁰ European Space Agency, ESTEC, Noordwijk, The Netherlands
¹¹ European Space Agency, ESAC, Villanueva de la Canada, Spain
¹² Physikalisch-Meteorologisches Observatorium Davos, World Radiation Center, Davos Dorf, Switzerland
¹³ ETH Zürich, IPA, Hönggerberg Campus, HIT J22.4, Wolfgang-Pauli-Str. 27, 8093 Zürich, Switzerland
¹⁴ ADNET Systems, Inc., Lanham, MD, USA
¹⁵ Department of Mathematics, Physics and Electrical Engineering, Northumbria University, Ellison Place, Newcastle Upon Tyne, NE1 8ST, UK
¹⁶ Department of Meteorology, University of Reading, Earley Gate, Reading, RG6 6BB, UK
¹⁷ Donostia International Physics Center (DIPC), San Sebastián, Spain

Received: 2 August 2023
Accepted: 11 February 2024

Abstract

Aims. We present an analysis of the first connection mosaic made by the SPICE instrument on board the ESA/NASA Solar Orbiter mission on March 2, 2022. The data will be used to map coronal composition that will be compared with in-situ measurements taken by SWA/HIS to establish the coronal origin of the solar wind plasma observed at Solar Orbiter. The SPICE spectral lines were chosen to have varying sensitivity to the first ionization potential (FIP) effect, and therefore the radiances of the spectral lines will vary significantly depending on whether the elemental composition is coronal or photospheric. We investigate the link between the behavior of sulfur and the hypothesis that Alfvén waves drive FIP fractionation above the chromosphere.

Methods. We performed temperature diagnostics using line ratios and emission measure (EM) loci, and computed relative FIP biases using three different approaches (two-line ratio (2LR), ratios of linear combinations of spectral lines (LCR), and differential emission measure (DEM) inversion) in order to perform composition diagnostics in the corona. We then compared the SPICE composition analysis and EUI data of the potential solar wind source regions to the SWA/HIS data products.

Results. Radiance maps were extracted from SPICE spectral data cubes, with values matching previous observations. We find isothermal plasma of around log T = 5.8 for the AR loops targeted, and that higher FIP-bias values are present at the footpoints of the coronal loops associated with two ARs. Comparing the results with the SWA/HIS data products encourages us to think that Solar Orbiter was connected to a source of slow solar wind during this observation campaign. We demonstrate FIP fractionation in observations of the upper chromosphere and transition region, emphasized by the behavior of the intermediate-FIP element sulfur.