Production and loss of electrons in the quiet daytime D region of the ionosphere
TL;DR: In this paper, the authors show that the presence of a steep ledge in electron density at an altitude that lies between 80 and 90 km, in the vicinity of the mesopause, cannot be related to a change in the primary production rate of electrons.
Abstract: Rocket probe measurements of the concentration of free electrons in the undisturbed daytime D region typically show the presence of a steep ledge in electron density at an altitude that lies between 80 and 90 km, in the vicinity of the mesopause. This paper is chiefly concerned with the interpretation of this feature. It is shown that the ledge cannot be related to a change in the primary production rate of electrons, and calculations based on existing knowledge of negative-ion reactions indicate that its presence is not likely to be related to negative-ion formation. We conclude that the ledge probably owes its existence to a sharp change in electron-positive-ion recombination coefficient, coinciding in altitude with the sharp change in nature of the dominant positive-ion species from molecular ions above the ledge to water vapor cluster ions below. The small electron densities below the ledge can be readily explained if the complex cluster ions have recombination coefficients of the order of 50 times larger than those of simple molecular ions at mesospheric temperatures. Such large recombination coefficients may be related to a new mode of recombination available to complex cluster ions, but not to the relatively simple molecular or atomic ions.
Citations
More filters
TL;DR: In this paper, the authors measured the nitric oxide density profile in the upper atmosphere between 70 and 110 km with scanning ultraviolet spectrometers aboard two Nike-Apache rockets on February 6 and January 31, 1969.
Abstract: The nitric oxide density profile in the upper atmosphere between 70 and 110 km was measured with scanning ultraviolet spectrometers aboard two Nike-Apache rockets on February 6 and January 31, 1969. The observed nitric oxide density profile has a maximum of about 108 cm−3 at 105 km, and a minimum of about 107 cm−3 at 85 km. Photochemical equilibrium is prevalent at about 85 km while mixing dominates below that altitude. A model in which nitric oxide is formed from N(2D) atoms can explain the observed features of the height profile. The contribution of nitric oxide ionization by solar Lyman-α to the total ion production is dominant in the middle D region (below 90 km) for the solar activity level at the time of the experiments. Dissociative recombination of nitric oxide ions is the main loss process in the region above 85 km. Below that height, a faster mechanism is required.
297 citations
TL;DR: In this article, a flowing afterglow system has been used to measure 296°K reaction rate constants and equilibrium constants for a number of negative ion reactions with atmospheric constituents, including negative ion hydration.
Abstract: A flowing afterglow system has been used to measure 296°K reaction rate constants and equilibrium constants for a number of negative ion reactions with atmospheric constituents. Three‐body association reactions of O−, OH−, O2−, O3−, Cl−, CO3−, OH−(H2O), and O2−(H2O) with H2O have been measured and association rate constants for several ions with CO2 and SO2 have been measured. A number of binary reactions for these ions and their hydrates have been measured with H2O, CO2, SO2, NO2, O3, and NO. Some equilibrium constants for negative ion hydration and some equilibrium constants for solvent (H2O, CO2, and SO2) exchange to several negative ions are reported.
275 citations
TL;DR: In this article, the positive ion composition was measured in the D- and E-regions above Sardinia during the maximum of the Geminid meteor Shower, during which a magnetic sector type mass spectrometer with dual collector and a liquid helium cryopump was used.
176 citations
TL;DR: In this paper, a model calculation has been carried out in which successive hydrations of NO + take place through clustering with N 2 and CO 2, followed by switching reactions with H 2 O. The results are in reasonably good agreement with observations as far as the water-cluster species are concerned.
112 citations
TL;DR: The solar proton event of July 13, 1982 was the largest to date in the current solar cycle as discussed by the authors, which led to the production of odd hydrogen radicals (H+OH+HO/sub 2/) which catalytically destroy odd oxygen in the mesosphere and stratosphee.
Abstract: The solar proton event of July 13, 1982 was the largest to date in the current solar cycle. Proton fluxes observed by the NOAA-6 satellite have been used to calculate ionization rates during the event, which have been found to be almost as large as those of the August, 1972 event near 70 km, but much smaller at lower altitudes. This ionization leads to the production of odd hydrogen radicals (H+OH+HO/sub 2/) which catalytically destroy odd oxygen in the mesosphere and stratosphee. A one-dimensional time-dependent model has been used to calculate the percentage change in ozone resulting from this event. The calculated ozone depletion is compared to that observed by the Solar Mesosphere Explorer (SME) satellite.
111 citations
References
More filters
TL;DR: A quadrupole mass spectrometer system employing a liquid nitrogen chilled zeolite pump has recently been developed for sampling positive ions at altitudes above 50 km as discussed by the authors, where the predominant ions detected within the D region (64 to 82 km) were 19+, 30+, and (37±1)+, with 32+ rapidly rising above 75 km approaching the abundance of 30+ at 83 km.
Abstract: A quadrupole mass spectrometer system employing a liquid nitrogen chilled zeolite pump has recently been developed for sampling positive ions at altitudes above 50 km. This system was flown successfully on a Nike Cajun rocket on October 31, 1963, at local noon from Eglin Air Force Base, Florida, and has provided the first positive ion composition measurements in the D region. The predominant ions detected within the D region (64 to 82 km) were 19+, 30+, and (37±1)+, with 32+ rapidly rising above 75 km approaching the abundance of 30+ at 83 km. At 82.5 km a sharp transition occurred in the spectrums, characterized by the rapid disappearance of 19+ and 37+ and instantaneous appearance of six new ion peaks. Five of these ion peaks are suggested to be the metallic ions of sodium (23+), magnesium (24+, 25+, 26+), and calcium (40+). The metallic ions all exhibited an identical altitude profile: a 10-km- wide peak with a maximum at 95 km, a minimum at 105 km, and then a continuous increase until apogee at 112 km. Above 82 km the ions 30+ and 32+ appear to be the most predominant, although many other minor constituent ions are present.
360 citations
TL;DR: The negative ion species produced in O2 and some gases containing oxygen have been surveyed for various pressure and E/p conditions using an rf mass spectrometer coupled to an electron drift tube operating at pressures up to 5 torr.
Abstract: The negative‐ion species produced in O2 and some gases containing oxygen have been surveyed for various pressure and E/p conditions using an rf mass spectrometer coupled to an electron drift tube operating at pressures up to 5 torr. The gases studied include O2, CO2, H2O, and CO as well as the mixtures CO2–O2, H2O–O2, CO–O2 at moderate and high E/p. When CO2 is present, O2− and O− are converted to CO4− and CO3−, respectively. The rate coefficients for these reactions at 300°K are approximately 1.3×10−29 and 8×10−29 cm6/sec, respectively. When H2O is present, complex ions such as (H2O)n·O2−, (H2O)n·O− and (H2O)n·OH− are formed with n≤5. In CO–O2 and H2–O2 mixtures, ion destruction, consistent with associative detachment of O−, has been observed to proceed with rate coefficients of about 10−9 cm3 sec−1.
197 citations
TL;DR: In this article, the rate constants for the loss processes of negative oxygen ions in the D -region of the ionosphere have been measured in the laboratory for the first time, and it was shown that the ozone to atomic oxygen ratio exceeds unity.
189 citations
TL;DR: In this paper, the formation of the observed water cluster ions H3O+, H5O2+, H7O3+, etc. in the D region of the earth's ionosphere has been studied.
Abstract: Laboratory studies of the ions produced by the addition of water vapor into flowing streams of O2+ (or NO+) ions have led to a vapor phase reaction scheme starting with O2+ that seems likely to be responsible for the formation of the observed water cluster ions H3O+, H5O2+, H7O3+, etc. in the D region of the earth's ionosphere. Experimental difficulties have precluded quantitative rate constant measurements so far, and in addition the D-region water vapor concentration is uncertain so that only a qualitative scheme is possible at this time. The O2(¹Δg) photoionization source recently proposed by Hunten and McElroy is presumed to be the necessary precursor O2+ source. The reaction scheme involves O4+ and O2+·H2O as intermediate ions; these ions are possibly present in observable concentrations in the D region. Nitrous acid (HNO2) production is proposed to be an end result of successive hydrations of atmospheric NO+. The hydration of the atmospheric NO+ and O2+ ions and the formation of O4+ are expected to increase somewhat the effective electron recombination coefficient in the ionosphere.
177 citations
TL;DR: The altitude profile of the infrared atmospheric system of oxygen at 1.27 μ in the dayglow has been measured using a two-channel filter photometer flown to an altitude of 128 km over White Sands, New Mexico, at a solar elevation of 14.5° in October 1966 as mentioned in this paper.
Abstract: The altitude profile of the infrared atmospheric system of oxygen at 1.27 μ in the dayglow has been measured using a two-channel filter photometer flown to an altitude of 128 km over White Sands, New Mexico, at a solar elevation of 14.5° in October 1966. The emission peaks at 49.5 km and the maximum volume emission rate is 1030 kR/km. The total emission intensity of 21 MR is in agreement with that of balloon-borne observations. The main emission layer agrees well with that predicted from an excitation mechanism of the photolysis of ozone in the Hartley continuum. There is some excess emission above 80 km, and three possible explanations are considered: additional ozone, enforced fluorescence via the ¹Σ level, and recombination of atomic oxygen. A combination of these can explain the observations, but which ones are most important cannot be decided. The amounts of metastable O2 observed above 70 km are sufficient to provide an important source of ionization and of NO in the lower D region.
159 citations