Mass spectrometric measurements of positive ions at altitudes from 64 to 112 kilometers

TLDR

A quadrupole mass spectrometer with a liquid‑nitrogen chilled zeolite pump was developed to sample positive ions above 50 km. The rocket flight on 31 Oct 1963 yielded the first D‑region positive‑ion spectra, revealing dominant 19+, 30+, 37±1+, and 32+ ions, a sharp transition at 82.5 km with the emergence of six new peaks—including metallic ions of Na, Mg, and Ca—whose abundance peaks at 95 km and rises again toward 112 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.