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SHocks: structure, AcceleRation, dissiPation

Periodic Reporting for period 1 - SHARP (SHocks: structure, AcceleRation, dissiPation)

Reporting period: 2021-01-01 to 2021-12-31

Shock waves are present in air and water on Earth and a wide range of plasmas in the universe. These plasmas are generally collisionless. The EU-funded SHARP project intends to contribute to understanding of the structure of collisionless shocks in diverse environments and the acceleration processes at all shock stages. The project will intensify exploitation of the heliospheric data and perform an inclusive comparative analysis of the Earth bow and planetary and interplanetary shocks. SHARP will combine the findings from in situ measurements of heliospheric and supernovae remnant shocks with remote observation of distant astrophysical shocks. The project will also develop a high-level database of shocks and innovative instruments for the shock analysis.
The overall aim of the SHARP project is to advance our understanding of the physics of charged particle acceleration and heating and collisionless dissipation in CSs across a range of scales in the Universe. Several key unresolved issues in the shock studies were identified in Annex 1 (Part B) with the approaches to attack them to reach main breakthrough. The rate of the data analysis being well below of the rate of the data acquisition was named as the important issue. SHARP first year efforts have been targeted to the thorough analysis of data for the terrestrial bow shocks from Cluster and MMS missions, planetary shocks on Mercury from Messenger spacecraft and astrophysical shocks from using supernova remnant observations by X-ray observatories such as NASA’s Chandra X-ray Observatory and ESA’s XMM-Newton observatory. This data analysis has been done in a close, day-to-day collaboration and joint work between all the SHARP partners. Non-sufficiency of previous collaborative efforts in the shock science community was stated as another issue but after SHARP first year, the collaboration between the leading experts in shock physics is well-established and will continue smoothly and effectively throughout the Project’s lifetime. The heliospheric observations provide in situ measured fields and particle data, which are unavailable for astrophysical shocks. The astrophysical observations provide indirect information about particle acceleration to high energies, unavailable in the heliosphere. During the first year of the research the two studies have been carried in parallel. Synthesis is planned for the third year.
The last issue of absence of a centralised shock database with a straightforward access to it for efficient exploitation of data has been addressed by developing the prototype of the online shock database containing shock crossings with parameters most beneficial to the scientific community. The efforts withint SHARP project during the first year resulted 9 papers (4 published as open access, 1 with SHARP team member participation without open access, 2 accepted and 2 submitted), publications were promoted on @FMIspace twitter, presented in 7 presentations, SHARP in general was presented to a general public in a lecture at BGU (in Hebrew). More publications and presentations are planned/in preparation.
Present state of art resembles a puzzle which consists of a number of disconnected assembled parts. For example, the structure of low-Mach number shocks is deduced from the observations at the Earth bow shock but the theory has not been verified up to now at other planetary shocks. Certain features of high-Mach number shocks have been deduced from observations but no theory exists which would explain the features and their dependence on the Mach number. Knowledge of the emission from accelerated and heated particles at SNR shocks is not and observations of heliosperic shocks are poorly connected. On the other hand, the amount of the available data collected in the heliosphere and in remote astrophysical observations is well beyond the capabilities of single researchers or even single groups. The first year of the research done in SHARP project has already successfully extended the theory of low-Mach number shock structure, developed for the terrestrial bow shock, to other low-Mach number shocks. We have already started to build a bridge connecting low- and high-Mach number shocks. The shock database is being quickly developed and filled with the data on shocks in a wide range of parameters.
Analysis of the low-Mach number shock structure