Effects of soft electron precipitation on the distribution of vibrational energy of N₂

Abstract

We have investigated the direct effect of soft electron precipitation on the nitrogen vibrational distribution and on the rate coefficient for the ion-atom interchange reaction between O + and N2 using a spectrum of the precipitating electrons characteristic of the dayside cusp region. Substantial increases in the nitrogen vibrational temperature and in the rate of the O + destruction reaction do not occur unless the flux of incident electrons is as large as 10 •2 cm -2 s -•. For such large fluxes, departures of the vibrational distribution from a Boltzmann distribution have a significant effect on the rate coefficient. Incident fluxes less than 10 • cm -2 s -•, such as are usually observed, have little direct effect on nitrogen vibration, although the indirect effect resulting from enhanced electron temperatures might be important.

Dayside cleft aurora and its ionospheric effects

“…nightside auroras but is not of major importance. Rees et alNewton et al [1977] considered the consequences of en-[1977] analyzed the coordinated data from rocket and satellite hanced N: vibrational populations. The importance of this nightside auroral observations and obtained good agreement question lies in the fact that there is a vibrational dependence with the calculated 6300-,4 emission, where the calculation was in the O + to N: ion-atom interchange rate, which is crucial in based on the measurement of primary auroral electrons.…”

An experimental test of the ionosphere electron gas cooling rate by excitation of the fine structure of the ground state of atomic oxygen

“…Apart from the uncertainties that are inherent in the theoretical and experimental cross sections employed in the derivation of these cooling rates, there is also the uncertainty that arises from the assumption that the rotational and vibrational state of excitation of these molecules is in local thermodynamic equilibrium at the thermospheric temperature. Departures from equilibrium in the state of vibrational excitation of N2 are believed to occur in the ionosphere, especially during the occurrence of SAR-ARCS, or during the precipitation of intense soft electron fluxes in the auroral regions [Newton et al, 1974[Newton et al, , 1977. Minor departures may also occur in heating experiments, since the presence of weak fluxes of extrathermal electrons, accelerated presumably by wave particle interactions, have been detected during such experiments.…”