Open AccessPitch angle distributions of energetic electrons at Saturn
Author(s) -
Carbary J. F.,
Mitchell D. G.,
Paranicas C.,
Roelof E. C.,
Krimigis S. M.,
Krupp N.,
Khurana K.,
Dougherty M.
Publication year - 2011
Publication title -
journal of geophysical research: space physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.67
H-Index - 298
eISSN - 2156-2202
pISSN - 0148-0227
DOI - 10.1029/2010ja015987
Subject(s) - saturn , pitch angle , electron , physics , electron precipitation , van allen radiation belt , magnetosphere , rings of saturn , computational physics , astronomy , plasma , nuclear physics , planet
Pitch angle distributions of energetic electrons (110–365 keV) at Saturn are statistically analyzed for 2005–2009. Using a nondipolar model magnetic field, pitch angle distributions are mapped to the magnetospheric equator and sorted by equatorial crossing distance. The results are quantified using a standard function for the pitch angle distribution, f( α ) = Asin K α (where α is the pitch angle and K is the power). Inside of ∼10 R S , the distributions are mostly peaked at 90° (K < 0), signifying a trapping distribution. Outside of this distance, the distributions are mostly field aligned (K > 0) with maxima near 0° and 180°. The 10 R S boundary maps to Saturn's ionosphere at latitudes equatorward of the aurora. Very few “flat” distributions are observed (K ≈ 0). The pitch angle distributions are not as well organized in local time as they are in radial distance, but over the 5 year survey between 10 and 20 R S field‐aligned distributions appear most often near midnight, while trapping distributions are found elsewhere.