Relativistic Electrons in the Earth’s Outer Radiation Belt
Special-Purpose Equipment Set for Correlated Investigations of the Dynamics of Relativistic Electron Fluxes in the Earth’s Outer Radiation Belt
Tech Area / Field
- SAT-EXP/Extraterrestrial Exploration/Space, Aircraft and Surface Transportation
- SAT-SAF/Space Safety/Space, Aircraft and Surface Transportation
3 Approved without Funding
Scientific Engineering Center SNIIP, Russia, Moscow
- Russian Academy of Sciences / Space Research Institute, Russia, Moscow\nNIIIT (Pulse Techniques), Russia, Moscow
- Southwest Research Institute, USA, TX, San Antonio\nJohns Hopkins University / Applied Physics Laboratory, USA, MD, Baltimore\nUniversity of Colorado at Boulder / Laboratory for Atmospheric and Space Physics, USA, CO, Boulder\nCalifornia Institute of Technology / Jet Propulsion Laboratory, USA, CA, Pasadena\nNASA / Goddard Space Flight Center, USA, MD, Greenbelt
Project summaryThe main objective of the Project is to find an optimal technological solution to the problem of forecasting the dynamics of relativistic electron fluxes in the outer radiation belt (ORB) of the Earth’s magnetosphere. The Project proposed envisages the development of methodology and hardware for experimental studies of electron fluxes in the ORB region over a wide range of energies (~0.1 to 10 MeV), of electric and magnetic fields, and electromagnetic waves there. Methods of rapid analysis of the dynamics of the parameters measured will also be developed within the Project as well as an algorithm for searching statistically significant correlations needed to identify and forecast radiation-hazardous increases of intensity of relativistic electron fluxes.
Wider activity of man in space and more active use of space-based facilities for numerous technological processes (systems for communications, navigation, remote sensing, etc.) have put forward the problems of spacecraft longevity and reliability. The adverse effect of several factors that determine the functioning resource of spacecraft, considerably increases the potential risk of satellite functioning.
The main factor of risk for satellites placed into orbits within the magnetosphere (from ionospheric to geostationary altitudes) is the radiation hazard caused by fluxes of charged particles in the radiation belts of the Earth (mainly these are protons and electrons). Many difficulties become evident when possible radiation loads are calculated for high-apogee orbits employed by most of scientific and commercial satellites. These orbits pass through the region of the outer radiation belt (ORB), the most dynamic region among all radiation belts of the Earth.
Observations show that geomagnetic disturbances are accompanied by considerable changes in the spatial structure and energy spectra of fluxes of energetic electrons which within the ORB region, dominate the main radiation doses in those orbits. Often such changes are accompanied by growing intensity of relativistic electron fluxes (sometimes up to two or three orders of magnitude). Here doses are also seriously rising and, respectively, satellite maintenance risks are also increasing.
Investigations of the longevity of operations of technological systems have revealed that about one third of all satellite operation failures observed, is associated with the fluxes of high-energy electrons. To a great extent this explains ever growing practical interest to the studies of the dynamics of ORB electron fluxes as well as the necessity to develop methods of forecasting changes in the ORB structure exposed to outer impact. The development of such forecasting methods meets serious difficulties because so versatile are versions of electron reactions to geomagnetic perturbations that in similar geomagnetic conditions fluxes of relativistic electrons may either increase or decrease. Note that for events accompanied by growing intensity of fluxes neither in the dynamics of the parameters of solar wind, nor in the dynamics of geomagnetic parameters was it possible to identify any specific features. It is implied by the absence of correlations between the behavior of relativistic electrons and the properties of solar wind (velocity, number density, the direction and intensity of magnetic field) and, respectively, geomagnetic indexes (Dst, Kp, AE) describing geomagnetic perturbations.
The models offered for describing the dynamics of electrons within the OBR (both theoretical and empirical) could not permit recognizing – among the entire available set of disturbing parameters – for each specific event the processes which are most effective in their impact on the dynamics of ORB electrons, or forecast, accurately enough, the anticipated dynamics.
At present it became obvious that the solution of the problem of ORB relativistic electron origin is, in many aspects, associated with or depends on, the acquisition of qualitative information as to how all magnetosphere parameters react to outer impact. The comprehensiveness and quality of the available information (e.g., a set of parameters to be measured, spatial, time and energy resolution of the instruments, etc.) are obviously insufficient to perform quantitative testing of theoretical work conclusions and to get confident predictions. To solve the problem of forecasting the dynamics of OBR electron fluxes, correlated measurements should be carried out, when, along with the measurements of electron fluxes over a wide energy range, measurements are being made of major magnetosphere parameters: magnetic and electric fields, electromagnetic waves. Here technical performance characteristics of measuring instrumentation should be chosen so as to permit comprehensive testing of the models offered. The Proposed Project “Special-purpose equipment set for correlated investigations of the dynamics of relativistic electron fluxes in the Earth’s outer radiation belt“, is intended to solve this problem, i.e. development of a special-purpose complex for correlated measurements of electron fluxes and of a number of magnetosphere parameters. During the Project realization a review of experimental data is planned, concerning the impact of geoactive factors on the dynamics of relativistic ORB electrons and on the dynamics of certain magnetosphere parameters.
As a result, a set of magnetosphere parameters would be proposed and selected as feasible, their measurements are to be conducted simultaneously with the measurements of electron fluxes. The work to be done should help select the most effective methodology procedure for measuring the parameters chosen, as well as determine the required sensitivity and accuracy of measurements and also graduate detecting systems.
Finally during the Project hardware and software should be developed for producing a specialized set of instrumentation; mathematical support is to be provided for rapid analysis of the parameters measured as well as an algorithm for identifying radiation-hazardous increases of fluxes of relativistic electrons.
The Project, when completed, would make it possible:
- to optimize a set of geoactive magnetosphere parameters for correlated investigations of the dynamics of ORB electron fluxes, to elaborate methods of rapid analysis and an algorithm for identifying radiation-hazardous enhancement of fluxes;
- to develop detection systems, software and hardware for the special-purpose equipment set;
- to perform lab testing of key elements of the equipment and to graduate the detection units.
The outcome would be preparation of the Technical Project and the experimental checking of most important parts of the measurement set, which further could be used as stand-by facility equipment for the global system supporting the Space Weather Survey.
This Project meets the ISTC goals and makes it possible to change over the effort of many scientists and engineers involved in the development and testing of nuclear weapons (NIIIT and SNIIP specialists) to the applied programs in space technology performed in the interests of Space Weather Survey, of finding solutions to urgent ecological problems, and of providing rapid warning about possible threat to the hardware and people involved.
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