ALBERT

Description: Maps of characterized auroral electron spectra, developed using eight years of particle spectrometer data from the Defense Meteorological Satellite Program (DMSP) suite of polar-orbiting spacecraft are presented. The electron spectra, which were sampled from both hemispheres, are categorized as either diffuse or accelerated. Diffuse spectra were best-fit with Maxwellian or kappa distributions and accelerated spectra were identified as displaying characteristics of either monoenergetic or broadband acceleration. A total of 30 million spectra were characterized, with 47.05 % being best-fit with Maxwellian distributions, 31.37 % being best-fit with kappa distributions, 12.20 % as monoenergetic, and 9.38 % as broadband. The spectra from both hemispheres were then binned in MLAT-MLT using a bin size of (MLAT, MLT) = (1 ∘ , 0.25 hr), for the ranges of 50 ∘ ≤ MLAT 〈 90 ∘ and 0000 ≤ MLT 〈 2400, and further separated into seven levels of K p . Within each MLAT-MLT-K p bin, the fraction of the bin total number of accelerated and best-fit spectra corresponding to each spectral type was calculated. Consideration of the global distribution of these fractions showed the following results. For K p 〈 2, diffuse electron spectra were predominantly best-fit by Maxwellian distributions. With increasing K p , more of the diffuse spectra were best-fit by Lorentzian distributions, especially within 0000 〈 MLT 〈 0600. For K p 〈 2, monoenergetic spectra occured throughout the oval at MLAT 〉 70 ∘ and broadband spectra occurred within 75 ∘ 〈 MLAT 〈 80 ∘ and the local time regions of 0600 〈 MLT 〈 1000 and 1300 〈 MLT 〈 1500. For K p ≥ 2, coverage of accelerated spectra varied with Kp. For low levels of Kp, accelerated spectra, primarily monoeneregetic spectra, predominated above. With increasing activity, broadband spectra covered more of the daytime MLT sectors, while diffuse spectra (Maxwellian and Lorentzian) became increasingly frequent on the nightside due to the poleward expansion of the diffuse precipitation region.