Abstract. On board the four Cluster spacecraft, the Cluster Ion Spectrometry (CIS) experiment measures the full, threedimensional ion distribution of the major magnetospheric ions (H + , He + , He ++ , and O + ) from the thermal energies to about 40 keV/e. The experiment consists of two different instruments: a COmposition and DIstribution Function analyser (CIS1/CODIF), giving the mass per charge composition with medium (22.5 • ) angular resolution, and a Hot Ion AnalCorrespondence to: H. Rème (Henri.Reme@cesr.fr) yser (CIS2/HIA), which does not offer mass resolution but has a better angular resolution (5.6 • ) that is adequate for ion beam and solar wind measurements. Each analyser has two different sensitivities in order to increase the dynamic range.
With the advent of the Heliophysics/Geospace System Observatory (H/GSO), a complement of multi-spacecraft missions and ground-based observatories to study the space environment, data retrieval, analysis, and visualization of space physics data can be daunting. The Space Physics Environment Data Analysis System (SPEDAS), a grass-roots software development platform (
www.spedas.org
), is now officially supported by NASA Heliophysics as part of its data environment infrastructure. It serves more than a dozen space missions and ground observatories and can integrate the full complement of past and upcoming space physics missions with minimal resources, following clear, simple, and well-proven guidelines. Free, modular and configurable to the needs of individual missions, it works in both command-line (ideal for experienced users) and Graphical User Interface (GUI) mode (reducing the learning curve for first-time users). Both options have “crib-sheets,” user-command sequences in ASCII format that can facilitate record-and-repeat actions, especially for complex operations and plotting. Crib-sheets enhance scientific interactions, as users can move rapidly and accurately from exchanges of technical information on data processing to efficient discussions regarding data interpretation and science. SPEDAS can readily query and ingest all International Solar Terrestrial Physics (ISTP)-compatible products from the Space Physics Data Facility (SPDF), enabling access to a vast collection of historic and current mission data. The planned incorporation of Heliophysics Application Programmer’s Interface (HAPI) standards will facilitate data ingestion from distributed datasets that adhere to these standards. Although SPEDAS is currently Interactive Data Language (IDL)-based (and interfaces to Java-based tools such as Autoplot), efforts are under-way to expand it further to work with python (first as an interface tool and potentially even receiving an under-the-hood replacement). We review the SPEDAS development history, goals, and current implementation. We explain its “modes of use” with examples geared for users and outline its technical implementation and requirements with software developers in mind. We also describe SPEDAS personnel and software management, interfaces with other organizations, resources and support structure available to the community, and future development plans.
Electronic Supplementary Material
The online version of this article (10.1007/s11214-018-0576-4) contains supplementary material, which is available to authorized users.
A human antibody facilitates opsonophagocytic killing, inhibits attachment of Pseudomonas aeruginosa, and exerts protective effects in several animal models of P. aeruginosa infection.
Lightning may be initiated via an electron avalanche that may occur when energetic electrons (~ 1 MeV) are accelerated by thunderstorm electric fields to velocities sufficient to produce new energetic electrons during ionizing collisions with nitrogen or oxygen molecules. For the avalanche to occur, the thunderstorm electric field must exceed a critical value called the breakeven field. At any altitude the breakeven field is substantially less than the field usually thought necessary either for dielectric breakdown or for streamer propagation. We show that 23 electric field soundings through thunderstorms seem to confirm that lightning occurs when the electric field exceeds the breakeven field. The soundings also show that the electric field inside storms tends to be limited to magnitudes less than or equal to the breakeven field. This breakeven mechanism may explain why electric field magnitudes greater than 150 kV m -• are rarely found inside thunderstorms. It may also help explain the initiation of lightning and other types of discharges that either propagate upward from the tops of thunderstorms or occur above them.
[1] The high-resolution germanium detector aboard the MAXIS (MeV Auroral X-ray Imaging and Spectroscopy) balloon payload detected nine X-ray bursts with significant flux extending above 0.5 MeV during an 18 day flight over Antarctica. These minutes-to-hours-long events are characterized by an extremely flat spectrum ($E
À2) similar to the first MeV event discovered in 1996, indicating that the bulk of parent precipitating electrons is at relativistic energies. The MeV bursts were detected between magnetic latitudes 58°-68°(L-values of 3.8-6.7) but only in the late afternoon/dusk sectors (14:30 -00:00 MLT), suggesting scattering by EMIC (electromagnetic ion cyclotron) waves as a precipitation mechanism. We estimate the average flux of precipitating E ! 0.5 MeV electrons to be $360 cm À2 s À1 , corresponding to about 5 Â 10 25 such electrons precipitated during the eight days at L = 3.8-6.7, compared to $2 Â 10 25 trapped 0.5-3.6 MeV electrons estimated from dosimeter measurements on a GPS spacecraft. These observations show that MeV electron precipitation events are a primary loss mechanism for outer zone relativistic electrons.
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