Solar Orbiter Key SWA Contributions

Current mission

The Solar Wind Analyser is a key component of the Solar Orbiter mission. SWA measures the in-situ solar wind, determining its speed, density and composition. Together with remote sensing instruments, SWA allows us to confidently relate the solar wind with its source regions.

SWA/EAS – Solar Wind ‘strahl’ electrons allows an independent determination of the direction of the magnetic field at the spacecraft, and, crucially, provides more global information on the nature of the magnetic field by providing a diagnosis of whether the local magnetic field line is connected to the Sun at one end, both ends or not at all;

Electron Strahl measured by SWA-EAS on Solar Orbiter — Fluxes of > 65 eV electrons ordered with respect to their propagation relative to the magnetic field direction (their 'pitch angle')

SWA/PAS – Measurements from this sensor are used to define the state of the solar wind itself (e.g. whether it is fast / slow), together with providing a key means to identify its structure (e.g. the passage of CME's, CIR's and shocks);

Proton and Alpha Particle Measurements by SWA/PAS — Measurements by SWA/PAS around the passage of a shock on 23rd March 2024.

SWA/HIS – Information on solar wind composition from this sensor provide the key connection to spectroscopic remote sensing measurements – providing a means to identify the solar source regions of the ambient solar wind passing the spacecraft.

Solar wind composition measurements made by SWA/HIS — Example of SWA/HIS composition measurements about an interplanetary shock encountered by Solar Orbiter on 12 May 2022. Panel (a): HIS E/q spectra at native 30-s resolution over a 2 h interval. Panels (b),(c): E/q-TOF distributions accumulated over 10-min before and after the shock, corresponding respectively to the orange-outlined intervals in panel (a). Taken from Livi, S., et al., First Results from the Solar Orbiter Heavy Ion Sensor, doi: 10.1051/0004-6361/202346304, A&A, 676, A36, 2023.

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Space Plasma Resources:
Beginners guide to space plasma physics
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Group Contact:
Name: Dr Daniel Verscharen (Head of Group)
Telephone: +44 (0) 1483 204 951
E-Mail: d.verscharen (at) ucl.ac.uk