Middle/Upper Atmosphere – Fieldwork (Past Research)
In October 2007 we participated in the launch of a large sounding rocket (HotPay-2) from the Andoya Rocket range in northern Norway (69o N). The Leeds group contributed a pair of photometers to the payload. Using very narrow-band interference filters, one of the photometers would measure the sum of the Na D-lines at 589.0 and 589.6 nm in the nightglow, and the other will measure just the D2 line 589.6 nm. We were thus hoping to obtain the absolute D-line emission, and the D2/D1 ratio, as a function of altitude between 80 and 105 km. In the previous years we had shown, in collaboration with Tom Slanger at SRI (Menlo Park, California), that the D2/D1 ratio is highly variable. Indeed, it is the only nightglow emission where the spin-orbit components are not constant. We have shown that the most likely explanation involves the low-lying excited state of NaO (formed by Na + O3 –> NaO(A) + O2), either reacting with O to generate D-line emission with a high D2/D1 ratio, or being quenched by O2 to NaO(X), which then reacts with O to generate D-line emission with a low ratio. In order to measure the absolute Na density and temperature, the rocket was tracked from the ground using a Na lidar at the ALOMAR observatory.
The HotPay-2 payload carried an additional three photometers to measure other components of the nightglow (Sodankyla Observatory, Finland and University of Stockholm); a charged dust detector (Dartmouth College, US), an ion probe and Faraday rotation system to measure positive ions and electrons, respectively (Graz Technical University, Austria); a device for measuring the spectrum of precipitating energetic electrons (Technical University of Kosice, Slovakia); and a cosmic ray detector (Bulgarian Academy of Sciences, Bulgaria).The rocket flew to ~380 km above an auroral arc, in order to measure upward-flowing field-aligned currents using a Search Coil Magnetometer (SCM) and Current Loop (CL) on booms that will deploy above 120 km.