Open AccessAnalysis of electron auroras based on the Monte Carlo method: Application to active electron arc auroras observed by the sounding rocket at Syowa Station
Author(s) -
Onda Kunizo,
Ejiri Masaki,
Itikawa Yukikazu
Publication year - 1999
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 - 10.1029/1999ja900323
Subject(s) - sounding rocket , electron , physics , atomic physics , monte carlo method , ionization , substorm , thermosphere , rocket (weapon) , flux (metallurgy) , range (aeronautics) , electron density , computational physics , ionosphere , ion , geophysics , materials science , magnetosphere , plasma , nuclear physics , statistics , mathematics , quantum mechanics , astronomy , engineering , metallurgy , composite material , aerospace engineering
A downward electron differential number flux, the absolute photoemission rate for the (0, 1) band of the first negative band system of the molecular nitrogen ion, and the number density of thermal electrons were simultaneously measured by the sounding rocket S‐310JA‐8 launched toward active auroral arcs at a substorm expansion phase on April 4, 1984, from Syowa Station in Antarctica. We apply the Monte Carlo method to analyze these observed results. The MSIS‐86 model is employed to represent the atmospheric number density and temperature in the aurora observed by this experiment. Only N 2 , O, and O 2 are taken into account as constituent elements of the atmosphere. Electrons are injected downward into the upper atmosphere at the altitude of 200 km, at which the downward electron differential number flux was measured. An initial electron energy is considered in the range of 0.1‐18 keV. It is assumed that an initial pitch angle is uniformly distributed in the range of [0, π/2]. Excitation and ionization rates of N 2 , O, and O 2 are calculated as a function of altitude, the initial pitch angle, and the initial electron energy. Production and emission rates of the N 2 + 1N (0, 1) band are deduced by using these calculated rates. Time variation of the observed absolute intensity of this band is reasonably well reproduced by the Monte Carlo method combined with the measured electron number flux.