Reanalysis of plasma measurements at geosynchronous orbit

Abstract

[1] Retrospective analyses of spacecraft anomalies, especially surface charging, require information about the local plasma environment. Such information is usually not available at geosynchronous orbit because most vehicles lack appropriate sensors. We have constructed a nearly continuous hourly database covering four plasma moments at geosynchronous orbit: density and temperature for hot (energies > 100 eV) protons and electrons. The four moments are provided for 24 hourly fiducial local time bins and cover the years 1990 --2005. We apply an ensemble of simple models to ''fill in'' the local time gaps between plasma measurements at geosynchronous orbit made by Los Alamos sensors. Validation on artificial data gaps shows that the reconstruction has rank order correlations ranging from 0.65 to 0.97, depending on bulk moment and local time. As a demonstration, we include a comparison of our reanalysis electron temperature to on-orbit surface charging measurements at a vehicle that lacks a plasma sensor. In addition to anomaly analyses, the reanalysis database we have produced can be used to provide geosynchronous boundary conditions for numerical simulations of the inner magnetosphere and temporal variations at a single location for statistical studies.Citation: O'Brien, T. P., and C. L. Lemon (2007), Reanalysis of plasma measurements at geosynchronous orbit, Space Weather, 5, S03007,

Superposed epoch analysis of a whistler instability criterion at geosynchronous orbit during geomagnetic storms

“…The whistler growth parameters could be examined for specification or re-analysis studies over a full solar cycle (e.g. O'Brien and Lemon, 2007). This technique could also be applied to other regions and other wave modes.…”

High-speed stream driven inferences of global wave distributions at geosynchronous orbit: relevance to radiation-belt dynamics

“…This may prove instructive in physics-based or reanalysistype modelling efforts (e.g. O'Brien & Lemon 2007;Varotsou et al 2008).…”

Comparison of simulated and observed trapped and precipitating electron fluxes during a magnetic storm

“…To specify the time‐varying electric field boundary conditions, we use the upstream‐driven Assimilative Model of Ionospheric Electrodynamics [ Richmond et al , ] reanalysis of Kihn and Ridley []. We map a combination of in situ Los Alamos National Laboratory (LANL)/Magnetospheric Plasma Analyzer (MPA) [ McComas et al ., 1993] and Synchronous Orbit Particle Analyzer (SOPA) [ Belian et al , ] proton and electron data (courtesy of LANL) and reanalysis of MPA data [ O'Brien and Lemon , ] from geosynchronous orbit to 10 R E to specify the plasma boundary conditions. Since we use the same magnetic field, electric field, and particle boundary conditions as in Chen et al [], we refer the reader to that paper for details.…”