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Abstract: The NOAA space environment center (SEC) facilitates the tracking and near real-time data distribution of interplanetary magnetic field, solar wind, and energetic particle observations from the advanced composition explorer near the Earth’s first Lagrangian point. In early 2004, the SEC switched from one set of low energy ion observations to another of a similar energy range. To assist users who now must rely upon a different set of observations, this manuscript documents the similarities and differences between the two sets of data. Although the two sets of observations are very similar most of the time, there are occasionally significant differences that users need to be aware of and must account for, especially those using data for operational purposes. [Copyright &y& Elsevier]

In an effort to characterize the response of the low energy magnetospheric measurements system (LEMMS) on the CASSINI spacecraft to energetic ions and electrons we have taken advantage of the excellent pre-launch beam calibrations in comparison to an extensive series of electron and ion Monte Carlo simulations. We selected the geometry and tracking toolkit to provide the framework for the instrument modeling and simulation environment. The results from these simulations match very well with the data collected during the instrument calibration. This gives us confidence that this simulation toolkit handles both electron and ion interactions in a reasonable fashion and that we can successfully apply this tool to regions of the spectrum where calibration data is not available. [Copyright &y& Elsevier]

Processes in the solar corona are prodigious accelerators of energetic ions, and electrons. The angular distribution, composition, and spectra of energetic particles observed near Earth gives information on the acceleration mechanisms. A class of energetic particle observations particularly useful in understanding the solar acceleration is the near-relativistic impulsive beam-like electron events. During five years of operation the Advanced Composition Explorer (ACE) has measured well over 400 electron events. Approximately 25% of these electron events are impulsive beam-like events that are released onto interplanetary field lines predominantly from western solar longitudes. We extend our initial ≈3 year study during the rise to solar maximum (; ) to a five year statistical analysis of these beam-like energetic electron events in relationship to optical flares, microwave emission, soft X-ray emission, metric and decametric type-III radio bursts, and coronal mass ejections. [Copyright &y& Elsevier]

All plasmas in the magnetosphere and interplanetary space contain non-thermal populations. Critical information on their acceleration mechanisms is provided by the slope of their energy spectra. The measurement of how energetic (non-thermal) electron spectra evolve in time provides fundamental information on how their acceleration processes develop. In an effort to characterize the response of current energetic particle instruments to energetic electrons we have taken advantage of the Geometry and Tracking toolkit (GEANT4) to provide the framework for an instrument model and a simulation environment. The results of these simulations match very well with data collected during various instrument calibration tests and give us confidence that GEANT4 handles electron interactions with matter in a reasonable fashion. The results of a specific Monte Carlo simulation (the response of the ACE/EPAM instrument to near-relativistic solar electron events) will be discussed. Given the usefulness of these simulations the GEANT4 toolkit has become an integral part of current and future energetic particle instrument development efforts. [Copyright &y& Elsevier]

Traditionally magnetic electron spectrometers provide the most reliable electron measurements in space at energies above ∼10 keV. However, the inclusion of powerful magnets presents problems for spacecraft with stringent magnetic cleanliness requirements, and the magnetic yoke required to close the instrument is bulky and heavy. To mediate the aforementioned shortcomings, we report a preliminary conceptual design on a new miniature magnetic electron spectrometer that measures energetic electrons from 50 keV to 1.5 MeV. The new detector covers close to 360° in the azimuthal direction and ± 3° off the plane, and if mounted on a spinning spacecraft, will measure the full spherical angular distribution twice per spin. This represents a very large advance over previous designs, which typically measure a very limited angular cone at any one time. As a result of the placement of the magnets in this design, the magnetic flux closes intrinsically, hence no bulky flux-containing magnetic yoke, typical in previous magnetic electron spectrometer designs, is required. We are funded by a NASA instrument development grant to develop a prototype of this sensor over the next 2 years. [Copyright &y& Elsevier]