Langmuir probe and ion acoustic velocity measurement of the concentration of two species in a multi-dipole plasma

2002 ◽  
Author(s):  
A.M. Hala ◽  
N. Hershkowitz
Keyword(s):  
Langmuir Probe ◽  
Velocity Measurement ◽  
Acoustic Velocity ◽  
Ion Acoustic

Short term characteristics of ion-acoustic type radio auroral echoes

1978 ◽  
Vol 56 (2) ◽  
pp. 292-301 ◽  
Author(s):  
Christos Haldoupis ◽  
George Sofko
Keyword(s):  
Signal Amplitude ◽  
Acoustic Velocity ◽  
Velocity Range ◽  
Short Term ◽  
Backscatter Signal ◽  
Ion Acoustic ◽  
Longitudinal Plasma ◽  
Digital Demodulation ◽  
Signal Fading ◽  
Time Sequences

Digital demodulation techniques and spectral analysis are used to study the short term (<1 s) characteristics of the ion-acoustic radio auroral echoes. Examination of 0.4 s time sequences indicates that the signal amplitude undergoes a deep and quasi-periodic fading with strongly marked periodicities in the 2–10 Hz range. Evidence shows that the fading is not due to interference but to the appearance and disappearance of independent scatterers, causing a sequence of backscatter signal bursts. If the assumption is made that these scatterers are longitudinal plasma density waves, the observed signal fading can be interpreted in terms of the growth and decay of individual regions of plasma instability rather than as interference between signals from separated coexisting scattering regions. Investigation of a large number of records suggests the following features for the irregularities associated with the ion-acoustic echoes: (1) their lifetime is in the 0.05–0.25 s range. (2) their growth (or decay) rate is in the 10–60 s−1 range, (3) their velocity remains fairly constant, even during growth and decay, and is always within the ion-acoustic velocity range in the medium.

Alternative spectral formulations for acoustic velocity measurement

1987 ◽  
Vol 81 (6) ◽  
pp. 1955-1961 ◽  
Author(s):  
Glen C. Steyer ◽  
Rajendra Singh ◽  
Donald R. Houser
Keyword(s):  
Velocity Measurement ◽  
Acoustic Velocity
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