First results from the Solar Orbiter Heavy Ion Sensor

¹ Space Science and Engineering, Southwest Research Institute, 6220 Culebra Rd., San Antonio, TX 78238, USA
² University of Michigan, Department of Climate and Space Sciences & Engineering, Climate and Space Research Building, 2455 Hayward St., Ann Arbor, MI 48109, USA
e-mail: slepri@umich.edu
³ Center for Astrophysics | Harvard & Smithsonian, 60 Garden Street, Cambridge, MA 02138, USA
⁴ NASA Goddard Space Flight Center, Heliophysics Division, 8800 Greenbelt Road, Greenbelt, MD 20771, USA
⁵ NASA Goddard Space Flight Center, Solar System Exploration Division, 8800 Greenbelt Road, Greenbelt, MD 20771, USA
⁶ Physics Institute, University of Bern, Sidlerstrasse 5, 3012 Bern, Switzerland
⁷ Institut de Recherche en Astrophysique et Planétologie, 9, Avenue, du Colonel ROCHE, BP 4346, 31028 Toulouse Cedex 4, France
⁸ University of New Hampshire, Space Science Center, 8 College Rd, Durham, NH 03824, USA
⁹ University College London, Department of Space and Climate Physics, Mullard Space Science Laboratory, Holmbury St. Mary, Dorking, Surrey RH5 6NT, UK
¹⁰ Imperial College London, South Kensington Campus, London SW7 2AZ, UK
¹¹ INAF-IFSI, Via del Fosso del Cavaliere 100, 00133 Rome, Italy
¹² Heliospheric Physics Lab. Heliophysics Science Division, NASA- Goddard Space Flight Center., 8800 Greenbelt Rd., Greenbelt, MD 20770, USA

Received: 2 March 2023
Accepted: 10 May 2023

Abstract

Aims. Solar Orbiter launched in February 2020 with the goal of revealing the connections between the Sun’s interior, atmosphere, and the heliosphere. The Solar Orbiter Heavy Ion Sensor (HIS) is a time-of-flight ion mass spectrometer dedicated to measuring heavy ions in the solar wind.

Methods. We present an overview of the first measurements of heavy ion composition from HIS, reviewing the methods used to transform the spectra obtained on board into scientific data products and examining two solar wind case studies as well as the statistical properties of the heavy ion composition observed by HIS. We also carried out a comparison with prior measurements of heavy ions at L1.

Results. The HIS data set provides the first mass- and charge-resolved heavy ion measurements in the inner heliosphere.

Conclusions. These high temporal resolution data have the potential to transform our understanding of the connections between the solar wind and its origin at the Sun, as well as the interaction between the solar wind and the environment around planets, comets, and in the interstellar medium.