Prediction of relativistic electron flux at geostationary orbit following storms: Multiple regression analysis. Issue 9 (18th September 2014)

• Record Type: Journal Article
• Authors: Simms, Laura E.; Pilipenko, Viacheslav; Engebretson, Mark J.; Reeves, Geoffrey D.; Smith, A. J.; Clilverd, Mark
• Is Part Of: Journal of geophysical research. Volume 119:Issue 9(2014:Sep.)
• Page Start: 7297
• Page End: 7318
• Publication Date: 2014-09-18
• Subjects: Magnetospheric physics -- Periodicals; Space environment -- Periodicals; Cosmic physics -- Periodicals; Planets -- Atmospheres -- Periodicals; Heliosphere (Astrophysics) -- Periodicals; Geophysics -- Periodicals; 523.01
• DOI: 10.1002/2014JA019955
• Languages: English
• ISSNs: 2169-9380

Abstract

<abstract abstract-type="main"> <title>Abstract</title> <p>Many solar wind and magnetosphere parameters correlate with relativistic electron flux following storms. These include relativistic electron flux before the storm; seed electron flux; solar wind velocity and number density (and their variation); interplanetary magnetic field <italic>B<sub>z</sub></italic>, <italic>AE</italic> and <italic>Kp</italic> indices; and ultra low frequency (ULF) and very low frequency (VLF) wave power. However, as all these variables are intercorrelated, we use multiple regression analyses to determine which are the most predictive of flux when other variables are controlled. Using 219 storms (1992–2002), we obtained hourly averaged electron fluxes for outer radiation belt relativistic electrons (>1.5 MeV) and seed electrons (100 keV) from Los Alamos National Laboratory spacecraft (geosynchronous orbit). For each storm, we found the log<sub>10</sub> maximum relativistic electron flux 48–120 h after the end of the main phase of each storm. Each predictor variable was averaged over the 12 h before the storm, the main phase, and the 48 h following minimum <italic>Dst</italic>. High levels of flux following storms are best modeled by a set of variables. In decreasing influence, ULF, seed electron flux, <italic>Vsw</italic> and its variation, and after‐storm <italic>B<sub>z</sub></italic> were the most significant explanatory variables. <italic>Kp</italic> can be added to the model, but it adds no further explanatory power. Although we included ground‐based VLF power from Halley, Antarctica, it shows little predictive ability. We produced predictive models using the coefficients from the regression models and assessed their effectiveness in predicting novel observations. The correlation between observed values and those predicted by these empirical models ranged from 0.645 to 0.795.</p> </abstract>