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First in‐situ observations of neutral and plasma density fluctuations within a PMSE layer
Author(s) -
Lübken FranzJosef,
Lehmacher Gerald,
Blix Tom,
Hoppe UlfPeter,
Thrane Eivind,
Cho John,
Swartz Wesley
Publication year - 1993
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/93gl00851
Subject(s) - physics , turbulence , electron density , plasma , altitude (triangle) , radar , atmospheric sciences , f region , spectral line , atomic physics , ionosphere , computational physics , geophysics , meteorology , astronomy , telecommunications , geometry , mathematics , quantum mechanics , computer science
The NLC‐91 rocket and radar campaign provided the first opportunity for high resolution neutral and plasma turbulence measurements with simultaneous observations 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 neutral 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 fluctuations are much stronger in the lower layer, the higher absolute electron density of the upper layer more than compensated for the weaker fluctuations yielding comparable radar echo powers.