The Energetic Particle Detector (EPD) onboard Solar Orbiter is a suite of multiple sensors (Suprathermal Electrons Protons, STEP; Suprathermal Ion Spectrograph, SIS; Electron Proton Telescope, EPT; High Energy Telescope, HET), which measures particle intensities over a wide range of energies (from suprathermal to relativistic energies) and for different species (electron, protons, and heavy ions) in different directions. The EPD data center (http://espada.uah.es/epd) offers a primer venue to inspect the Solar Energetic Particle (SEP) activity, both to promptly check the most recent solar activity using quicklook plots based on low-latency data sets, and to perform deeper studies with data validated for scientific use. Among others, a series of plots and relevant information, such as the spacecraft maneuvers or sensor updates, are provided to the community. This facility gives access to all the data from the EPD sensors (which can be also found in the Solar Orbiter Archive), including Level 2 (calibrated) as well as more elaborated Level 3 data in the near future, which have further processing. An application programming interface (API) is also offered for accessing EPD data. Besides, during the first year and a half of observations, Solar Orbiter has completed three orbits, and EPD has measured several increases in particle fluxes, due to heliospheric and solar-origin events. Some of the events have been analysed and the flux enhancements have been tagged for future studies. This work aims to let the community know the availability of the instrument data products, and to explain how to properly use the provided data products and plots, as well as to summarise all the available studies published until now.

This White Paper outlines the importance of addressing the fundamental science theme “How are charged particles energized in space plasmas” through a future ESA mission. The White Paper presents five compelling science questions related to particle energization by shocks, reconnection, waves and turbulence, jets and their combinations. Answering these questions requires resolving scale coupling, nonlinearity, and nonstationarity, which cannot be done with existing multi-point observations. In situ measurements from a multi-point, multi-scale L-class Plasma Observatory consisting of at least seven spacecraft covering fluid, ion, and electron scales are needed. The Plasma Observatory will enable a paradigm shift in our comprehension of particle energization and space plasma physics in general, with a very important impact on solar and astrophysical plasmas. It will be the next logical step following Cluster, THEMIS, and MMS for the very large and active European space plasmas community. Being one of the cornerstone missions of the future ESA Voyage 2050 science programme, it would further strengthen the European scientific and technical leadership in this important field.