Abstract
High-energy charged particles in the van Allen radiation belts and in solar energetic particle events can damage satellites on orbit leading to malfunctions and loss of satellite service. Here we describe some recent results from the SPACECAST project on modelling and forecasting the radiation belts, and modelling solar energetic particle events. We describe the SPACECAST forecasting system that uses physical models that include wave-particle interactions to forecast the electron radiation belts up to 3 h ahead. We show that the forecasts were able to reproduce the >2 MeV electron flux at GOES 13 during the moderate storm of 7–8 October 2012, and the period following a fast solar wind stream on 25–26 October 2012 to within a factor of 5 or so. At lower energies of 10 – a few 100 keV we show that the electron flux at geostationary orbit depends sensitively on the high-energy tail of the source distribution near 10 RE on the nightside of the Earth, and that the source is best represented by a kappa distribution. We present a new model of whistler mode chorus determined from multiple satellite measurements which shows that the effects of wave-particle interactions beyond geostationary orbit are likely to be very significant. We also present radial diffusion coefficients calculated from satellite data at geostationary orbit which vary with Kp by over four orders of magnitude. We describe a new automated method to determine the position at the shock that is magnetically connected to the Earth for modelling solar energetic particle events and which takes into account entropy, and predict the form of the mean free path in the foreshock, and particle injection efficiency at the shock from analytical theory which can be tested in simulations.
Highlights
Between 2002 and 2012 the number of operational satellites at geosynchronous orbit has increased from approximately 200– 419, and the total number of satellites on orbit has risen to approximately 1,000 (Satellite Industry Association 2012)
In this paper we present some recent results from the SPACECAST project to forecast the high-energy electron radiation belts, and to model solar energetic particle events
The results of our studies can be summarized as follows: 1. We have developed the first system to forecast the highenergy electron radiation belt flux that uses physical models which include wave-particle interactions
Summary
Between 2002 and 2012 the number of operational satellites at geosynchronous orbit has increased from approximately 200– 419, and the total number of satellites on orbit has risen to approximately 1,000 (Satellite Industry Association 2012). They are geosynchronous orbit at an altitude of 36,000 km, medium Earth orbit between 1000 and 36,000 km, and low earth orbit, less than 1000 km All these satellites are at risk from space weather, where the most serious hazards come from high-energy charged particles trapped in the van Allen radiation belts, and very high-energy cosmic rays and solar energetic particles (SEPs) which penetrate through the Earth’s magnetic field. One important element of this project is to develop a forecasting system based on physical models which include wave-particle interactions
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