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Detection and Analysis of Plasma Bubbles at 20 MHz

scintillation.jpg

"DETECTION AND ANALYSIS OF PLASMA BUBBLES AT 20 MHz RADIO FREQUENCY"
 
by Professors John C. Mannone and Wanda Diaz
Society of Amateur Radio Astronomers 2004 Conference
Tuesday June 29, 2004
National Radio Astronomy Observatory
Green Bank, WV 
 
ABSTRACT:
Charge deficient holes in the F-region, called plasma bubbles, are typically detected above the equatorial zone. Some of the traditional techniques of detection involve sensitive receivers called riometers tuned to 30 MHz to record time variations or  rocket-borne Langmuir probes measure the fluctuation of electron number density. In this work, the electron number density variations are recorded indirectly. Astrophysical radio waves are modulated by these variations as they travel through the ionosphere.  Spectral analysis of decametric radio signals acquired with 20 MHz antennas will provide similar information about the ionosphere. The behavior of the radio noise floor will show if radio light is scintillated. This technique is applied to data from Puerto Rico. Though just north of the magnetic equatorial zone, power spectra disclose radio twinkling by the sudden post-sunset onset of plasma bubbles just before local midnight. ***********************************************************************
Subsequent work was done and published, but on a different aspect of the data:

Sun and Geosphere, 2008; 3(1): 42 - 45 ISSN 1819-0839
Sonification for the Analysis of Plasma Bubbles at 21 MHz, Wanda L. Diaz-Merced 1, Robert M. Candey 2, John C. Mannone 3, David Fields 3, Emilio Rodriguez 3

1 Glasgow Interactive Systems Group, Department of Computing Science, University of Glasgow, UK
2 NASA, GSFC, Greenbelt, Maryland, USA
3 Shirohisa Ikeda Project Gurabo, Puerto Rico 

Slide 1: THEORETICAL & SIMULATED PLASMA BUBBLES
plumemodel.jpg
Jicarma Radar Plasma Density Scans Model Data Input (see note below)

Slide 2: Log P vs. Log f PLOT: 4 HRS POSTSUNSET
03zloglog.jpg
Analysis of radio noise floor between the roll-off and diffraction filtering limits

Slide 3: TIME EVOLUTION OF SPECTRAL INDEX
dpdt.jpg
Plasma Bubble formation is strongly suggested over Puerto Rico 7Jun 04 at 03Z

Read "Plasma Bubbles" Radio Poetry

Link to another site withthe full presentation (4.4 MB PPT)

Note: Slides of plasma models adapted from Future Directives in Ionospheric Space Weather Applications, AGU, Dec 01, D. Decker, et al., Air Force Research Laboratories, Space Vehicle Directorate.

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