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Over the last decade, efforts have been made in the radiation belt community to develop data assimilation tools in order to improve the accuracy of radiation belts models. In this paper we present a new method to correctly take into account the outer boundary conditions at L* = 8 in such an enhanced model of the radiation belts. To do that we based our work on the Time History of Events and Macroscale Interactions during Substorms/Solid State Telescope data set. Statistics are developed to define a consistent electron distribution at L* = 8 (in both equatorial pitch angle and energy), and a variance-covariance matrix is estimated in order to more realistically drive the Monte Carlo sampling required by the Ensemble Kalman Filter (EnKF). Data processing is first described as well as caveats avoided, and then the use of these information in a machinery such as the EnKF is described. It is shown that the way the Monte Carlo simulations are performed is of great importance to realistically reproduced outer boundary distribution needed by the physic-based Salammbo model. Finally, EnKF simulations are performed and compared during September 2011 in order to analyze the improvements gained using this new method of defining outer boundary conditions. In particular, we highlight in this study that such a method provides great improvement in the reconstruction of the dynamics observed at geosynchronous orbit, both during quiet and active magnetic conditions.

Radiation effects in a fixed-point digital signal processor (DSP) from Texas Instruments were studied. Single event upset, single event snapback and total ionizing dose effects were observed and some comparisons to other studies of floating-point DSPs are made.

Laser tests performed on a prototype chip to validate new SEU-hardened storage cell designs revealed unexpected latch-up and single-event upset phenomena. The investigations that identified their location show the existence of a topology-dependent dual node upset mechanism. Design solutions are suggested to avoid its occurrence.

Experimental equipment for performing heavy-ion testing on programmable integrated circuits is presented. The equipment was used along with two different types of heavy-ion simulator to perform SEU (single-event-upset) tests on representative circuits: a dedicated Cf/sup 252/ fission decay source and an 88-in cyclotron. The observed discrepancies between the two results obtained cast doubt on the validity of using californium sources to simulate high-LET (linear-energy-transfer) particles. >