The Solar Wind Electron (SWE) instrument measures the 3D distribution of highly energetic electrons found in the solar wind. SWE is optimized to measure in situ solar wind electrons at L1 to provide context for the ENA measurements and perform the in situ solar wind observations necessary to understand the local structures that can affect acceleration and transport of these particles.
SWE consists of a curved-plate electrostatic analyzer (ESA) composed of nested 120° spherical, grooved, and blackened aluminum alloy plates, and seven channel electron multiplier (CEM) detectors. Electrons enter the ESA through a fan-shaped aperture directed radially out the side of the IMAP spacecraft. This entry point is engineered such that only electrons within a narrow range of energies and directions (angles) pass through and are detected. Each CEM detector possesses a fan-shaped field of view (FOV) that allows the instrument to view the entire strip of sky parallel to the instrument as the IMAP spacecraft spins, missing only a few small areas. The high resolution of energies and flow angles will allow for a full characterization of the solar wind electron distributions that include an energy spectrum of energetic particle populations.
SWE - together with SWAPI, MAG, CoDICE, and HIT - also provides near real-time measurements for the IMAP Active Link for Real-Time (I-ALiRT) space weather monitoring service. With I-ALiRT, IMAP will enable new ways of forecasting space weather by streaming near real-time observations of conditions headed towards Earth to operators on the ground, increasing our awareness and understanding of space weather drivers before they can reach Earth.
SWE design and assembly is led by Los Alamos National Laboratory (LANL) in collaboration with Southwest Research Institute (SwRI).