FIRST IN-SITU OBSERVATIONS OF NEUTRAL AND PLASMA DENSITY FLUCTUATIONS WITHIN A P MSE LAYER

• Main Authors: Franz-josef Liibken, Gerald Lehmacher, Tom Blix, Eivind Thrane, John Cho, Wesley Swartz
• Other Authors: The Pennsylvania State University CiteSeerX Archives
• Format: Text
• Language: English
• Subjects: EISCAT
• Online Access: http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.488.2176; http://www.iap-kborn.de/fileadmin/user_upload/MAIN-abteilung/optik/Mitarbeiter/Luebken/publication/Luebken-GRL-93.pdf

Abstrect. The NLC-91 rocket and radar campaign pro-vided the first opportunity for high resolution neutral and plasma turbulence measurements with simultaneous ob-servations of PMSE (Polar Mesospheric Summer Echoes). During the flight of the TURBO payload on August 1, 1991, CUPRI and EISCAT observed double PMSE layers located at 86 and 88 km altitude, respectively. Strong neu-tral density fluctuations were observed in the upper layer but not in the lower layer. The fluctuation spectra of the ions and neutrals within the upper layer are consistent with standard turbulence theories. However, we show that there is no neutral turbulence present in the lower layer and that something else must have been operating here to create the plasma fluctuations and hence the radar echoes. Although the in situ measurements of the electron density fluctua-tions are much stronger in the lower layer, the higher ab-solute electron density of the upper layer more than com-pensated for the weaker fluctuations yielding comparable radar echo powers.