Morley S.K.,Space Science and Applications |
Friedel R.H.W.,Space Science and Applications |
Spanswick E.L.,Space Science and Applications |
Spanswick E.L.,University of Calgary |
And 5 more authors.
Proceedings of the Royal Society A: Mathematical, Physical and Engineering Sciences | Year: 2010
We present a statistical study of relativistic electron counts in the electron radiation belt across a range of drift shells (L* >4) combining data from nine combined X-ray dosimeters (CXD) on the global positioning system (GPS) constellation. The response of the electron counts as functions of time, energy and drift shell are examined statistically for 67 solar wind stream interfaces (SIs); two-dimensional superposed epoch analysis is performed with the CXD data. For these epochs we study the radiation belt dropouts and concurrent variations in key geophysical parameters. At higher L* we observe a tendency for a gradual drop in the electron counts over the day preceding the SI, consistent with outward diffusion and magnetopause shadowing. At all L*, dropouts occur with a median time scale of ≃7 h and median counts fall by 0.4-1.8 orders of magnitude. The central tendencies of radiation belt dropout and recovery depend on both L* and energy. For ≃70 per cent of epochs Sym-H more than -30 nT, yet only three of 67 SIs did not have an associated dropout in the electron data. Statistical maps of electron precipitation suggest that chorus-driven relativistic electron microbursts might be major contributors to radiation belt losses under high-speed stream driving. © 2010 The Royal Society.
Koller J.,Space Science and Applications
Advances in the Astronautical Sciences | Year: 2012
Space weather refers to the conditions on the sun and in the solar wind, magnetosphere, ionosphere, and thermosphere that can influence the performance and reliability of space-borne and ground-based technological systems and endanger human life or health. The purpose of this presentation is to review the processes and effects on space hardware with relevance to real world applications. We will focus on the inner magnetosphere and in particular on the radiation belt environment. We will describe the impact of space weather on hardware as a function of orbit and discuss the current modeling efforts that take into account real-time radiation belt observations and a physics-based model.