Comparison of LIF and solid electrolyte sensor measurements of atomic oxygen in a plasma jet

Author(s):  
Markus Feigl ◽  
Joseph Dennis ◽  
Stefanos Fasoulas ◽  
Monika Auweter-Kurtz
2015 ◽  
Vol 8 (3) ◽  
pp. 3245-3282 ◽  
Author(s):  
M. Eberhart ◽  
S. Löhle ◽  
A. Steinbeck ◽  
T. Binder ◽  
S. Fasoulas

Abstract. The atmospheric energy budget is largely dominated by reactions involving atomic oxygen (O). Modeling of these processes requires detailed knowledge about the distribution of this oxygen species. Understanding the mutual contributions of atomic oxygen and wave motions to the atmospheric heating is the main goal of the rocket campaign WADIS. It includes, amongst others, two of our instruments for the measurement of atomic oxygen that have both been developed with the aim of resolving density variations on small vertical scales along the trajectory. In this paper the instrument based on catalytic effects (PHLUX) is introduced briefly. The experiment employing solid electrolyte sensors (FIPEX) is presented in detail. These sensors were laboratory calibrated using a microwave plasma as a source for atomic oxygen in combination with mass spectrometer reference measurements. The spectrometer was in turn calibrated for O with a method based on methane. In order to get insight into the horizontal variability the rocket payload had instrument decks at both ends. Each housed several sensor heads measuring during both the up- and downleg of the trajectory. The WADIS campaign comprises two rocket flights during different geophysical conditions. Results from WADIS-1 are presented which was successfully launched in June 2013 from Andøya Rocket Range, Norway. FIPEX data was sampled with 100 Hz and yield atomic oxygen density profiles with a vertical resolution better than 10 m. Numerical simulations of the flow field around the rocket were done at several points of the trajectory to assess the influence of aerodynamic effects on the measurement results. Density profiles peak at 3 × 1010 cm−3 at altitudes of 93.6 and 96 km for up- and downleg respectively.


2018 ◽  
Author(s):  
Martin Eberhart ◽  
Stefan Löhle ◽  
Boris Strelnikov ◽  
Jonas Hedin ◽  
Mikhail Khaplanov ◽  
...  

Abstract. Absolute profiles of atomic oxygen number densities with high vertical resolution have been determined in the MLT region from in-situ measurements by several rocket-borne solid electrolyte sensors. The amperometric sensors were operated in both controlled and uncontrolled modes and with various orientations on the fore and aft deck of the payload. Calibration was based on mass spectrometry in a molecular beam containing atomic oxygen produced in a microwave discharge. The sensor signal is proportional to the number flux onto the electrodes and the mass flow rate in the molecular beam was measured additionally to derive this quantity from the spectrometer reading. Numerical simulations provided aerodynamic correction factors to derive the atmospheric number density of atomic oxygen from the sensor data. The flight results indicate a preferable orientation of the electrode surface perpendicular to the rocket axis. While unstable during the upleg, the density profiles measured by these sensors show an excellent agreement with the atmospheric models and photometer results during the downleg of the trajectory. The high spatial resolution of the measurements allows the identification of small-scaled variations in the atomic oxygen concentration.


2019 ◽  
Author(s):  
Igor Hörner ◽  
Rainer Öfele ◽  
Martin Eberhart ◽  
Stefan Loehle ◽  
Stefanos Fasoulas

Sign in / Sign up

Export Citation Format

Share Document