Effect of Meteoric Dust on the Effective Recombination Coefficient in the Lower Ionosphere

Radio Science ◽  
1966 ◽  
Vol 1 (12) ◽  
pp. 1401-1408 ◽  
Author(s):  
R. Parthasarathy ◽  
D. B. Rai
Keyword(s):  
Lower Ionosphere ◽  
Recombination Coefficient ◽  
Meteoric Dust

scholarly journals Influence of water vapour on the height distribution of positive ions, effective recombination coefficient and ionisation balance in the quiet lower ionosphere

2014 ◽  
Vol 32 (3) ◽  
pp. 207-222 ◽  
Author(s):  
V. Barabash ◽  
A. Osepian ◽  
P. Dalin
Keyword(s):  
Water Vapour ◽  
Electron Density ◽  
Electron Number Density ◽  
Lower Ionosphere ◽  
Recombination Coefficient ◽  
Height Distribution ◽  
Number Density ◽  
Electron Number ◽  
Water Vapour Concentration ◽  
Vapour Concentration

Abstract. Mesospheric water vapour concentration effects on the ion composition and electron density in the lower ionosphere under quiet geophysical conditions were examined. Water vapour is an important compound in the mesosphere and the lower thermosphere that affects ion composition due to hydrogen radical production and consequently modifies the electron number density. Recent lower-ionosphere investigations have primarily concentrated on the geomagnetic disturbance periods. Meanwhile, studies on the electron density under quiet conditions are quite rare. The goal of this study is to contribute to a better understanding of the ionospheric parameter responses to water vapour variability in the quiet lower ionosphere. By applying a numerical D region ion chemistry model, we evaluated efficiencies for the channels forming hydrated cluster ions from the NO+ and O2+ primary ions (i.e. NO+.H2O and O2+.H2O, respectively), and the channel forming H+(H2O)n proton hydrates from water clusters at different altitudes using profiles with low and high water vapour concentrations. Profiles for positive ions, effective recombination coefficients and electrons were modelled for three particular cases using electron density measurements obtained during rocket campaigns. It was found that the water vapour concentration variations in the mesosphere affect the position of both the Cl2+ proton hydrate layer upper border, comprising the NO+(H2O)n and O2+(H2O)n hydrated cluster ions, and the Cl1+ hydrate cluster layer lower border, comprising the H+(H2O)n pure proton hydrates, as well as the numerical cluster densities. The water variations caused large changes in the effective recombination coefficient and electron density between altitudes of 75 and 87 km. However, the effective recombination coefficient, αeff, and electron number density did not respond even to large water vapour concentration variations occurring at other altitudes in the mesosphere. We determined the water vapour concentration upper limit at altitudes between 75 and 87 km, beyond which the water vapour concentration ceases to influence the numerical densities of Cl2+ and Cl1+, the effective recombination coefficient and the electron number density in the summer ionosphere. This water vapour concentration limit corresponds to values found in the H2O-1 profile that was observed in the summer mesosphere by the Upper Atmosphere Research Satellite (UARS). The electron density modelled using the H2O-1 profile agreed well with the electron density measured in the summer ionosphere when the measured profiles did not have sharp gradients. For sharp gradients in electron and positive ion number densities, a water profile that can reproduce the characteristic behaviour of the ionospheric parameters should have an inhomogeneous height distribution of water vapour.

Using the effective recombination coefficient to constrain the positive ion composition in Saturn's ionosphere

2020 ◽  
Author(s):  
Joshua Dreyer ◽  
Erik Vigren ◽  
Michiko Morooka ◽  
Jan-Erik Wahlund ◽  
Stephan Buchert ◽  
...  
Keyword(s):  
Electron Temperature ◽  
Recombination Rate ◽  
Lower Ionosphere ◽  
Negative Ions ◽  
Rate Coefficients ◽  
Recombination Coefficient ◽  
Positive Ions ◽  
Electron Production ◽  
Upper Limits ◽  
Positive Ion

<p>We combine RPWS/LP and INMS data from Cassini's Grand Finale orbits into Saturn's lower ionosphere to calculate the effective recombination coefficient α<sub>300</sub> at a reference electron temperature of 300 K. Assuming photochemical equilibrium at altitudes below 2500 km and using an established method to determine the electron production rate, we derive upper limits for α<sub>300</sub> of ∼ 2.5∗10<sup>-7</sup> cm<sup>3 </sup>s<sup>-1</sup>, which suggest that Saturn's ionospheric positive ions are dominated by species with low recombination rate coefficients.<br />An ionosphere dominated by water group ions or complex hydrocarbons, as previously suggested, is incompatible with this result, as these species have recombination rate coefficients > 5∗10<sup>-7</sup> cm<sup>3 </sup>s<sup>-1</sup> at an electron temperature of 300 K. The results do not give constraints on the nature of the negative ions.</p>

scholarly journals Constraining the Positive Ion Composition in Saturn’s Lower Ionosphere with the Effective Recombination Coefficient

2021 ◽  
Vol 2 (1) ◽  
pp. 39
Author(s):  
Joshua Dreyer ◽  
Erik Vigren ◽  
Michiko Morooka ◽  
Jan-Erik Wahlund ◽  
Stephan C. Buchert ◽  
...  
Keyword(s):  
Lower Ionosphere ◽  
Recombination Coefficient ◽  
Ion Composition ◽  
Positive Ion

Dynamical processes in the lower ionosphere

2003 ◽  
Vol 8 (5-6) ◽  
pp. 76-80 ◽  
Author(s):  
S.V. Panasenko ◽  
◽  
V.T. Rozumenko ◽  
O.F. Tyrnov ◽  
L.F. Chernogor ◽  
...  
Keyword(s):  
Lower Ionosphere ◽  
Dynamical Processes
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