The Supra Thermal Electron Proton (STEP) Sensor for Solar Orbiter: Detection Principle and Data Products

The Supra-Thermal Electron and Proton (STEP) sensor is one instrument of the Energetic Particle Detector (EPD) suite on Solar Orbiter. The STEP sensor onboard Solar Orbiter will provide measurements of suprathermal electrons and protons (ions) with an energy range from 2 keV to 80 keV in the ecliptic plane with a viewing direction along the average nominal parker spiral. With its unique design, STEP is capable of determining the angular distribution of the detected particles with high temporal resolution. Therefore STEP provides seed population measurements of Solar Energetic Particles (SEPs) and with these measurements insight into the acceleration mechanisms of these particles can be achieved. Due to its excellent energy resolution STEP can improve the current prediction models for heliospheric electron propagation during type III burst events. To achieve these unique measurements, the STEP unit features two sensor heads, each with a pixelated detector able to distinguish 15 different field of view vectors. The proton/ion sensor head utilizes a magnet system to suppress electrons. Using the proton/ion data, the electron sensor data can be corrected. Here we introduce the detection technique, instrument capabilities and the available data products of the STEP sensor.