9.9.13

NASA: IONOSPHERIC MODIFICATION


U.S. Navy photo by Chief Mass communication Specialist Ryan J. Courtade

by NASA

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Ionospheric modification using relativistic electron beams

 
No Digital Version Available: Request from CASI
Author and Affiliation:
Banks, Peter M.(Stanford Univ.; CA, United States);
Fraser-Smith, Anthony C.(Stanford Univ.; CA, United States);
Gilchrist, B. E.(Stanford Univ.; CA, United States)
Abstract: The recent development of comparatively small electron linear accelerators (linacs) now makes possible a new class of ionospheric modification experiments using beams of relativistic electrons. These experiments can potentially provide much new information about the interactions of natural relativistic electrons with other particles in the upper atmosphere, and it may also make possible new forms of ionization structures extending down from the lower ionosphere into the largely un-ionized upper atmosphere. The consequences of firing a pulsed 1 A, 5 Mev electron beam downwards into the upper atmosphere are investigated. If a small pitch angle with respect to the ambient geomagnetic field is selected, the beam produces a narrow column of substantial ionization extending down from the source altitude to altitudes of approximately 40 to 45 km. This column is immediately polarized by the natural middle atmosphere fair weather electric field and an increasingly large potential difference is established between the column and the surrounding atmosphere. In the regions between 40 to 60 km, this potential can amount to many tens of kilovolts and the associated electric field can be greater than the field required for breakdown and discharge. Under these conditions, it may be possible to initiate lightning discharges along the initial ionization channel. Filamentation may also occur at the lower end to drive further currents in the partially ionized gases of the stratosphere. Such discharges would derive their energy from the earth-ionosphere electrical system and would be sustained until plasma depletion and/or electric field reduction brought the discharge under control. It is likely that this artificially-triggered lightning would produce measurable low-frequency radiation.
Publication Date: Oct 01, 1990
Document ID:
19910009219
(Acquired Jun 04, 2003)
Accession Number: 91N18532
Subject Category: GEOPHYSICS
Document Type: Conference Paper
Publication Information: AGARD, Ionospheric Modification and its Potential to Enhance or Degrade the Performance of Military Systems; 18 p
Publisher Information: United States
Contract/Grant/Task Num: NAGW-235
Financial Sponsor: NASA; United States
Organization Source: Stanford Univ.; Space, Telecommunications, and Radioscience Lab.; CA, United States
Description: 22p; In English
Distribution Limits: Unclassified; Publicly available; Unlimited
Rights: Copyright; Distribution within the U.S. granted by agreement
NASA Terms: ATMOSPHERIC IONIZATION; EARTH IONOSPHERE; ELECTRIC FIELDS; ELECTRON ACCELERATORS; IONOSPHERIC DISTURBANCES; LIGHTNING; LINEAR ACCELERATORS; LOWER IONOSPHERE; MIDDLE ATMOSPHERE; MILITARY TECHNOLOGY; RELATIVISTIC ELECTRON BEAMS; UPPER ATMOSPHERE
Imprint And Other Notes: In AGARD, Ionospheric Modification and its Potential to Enhance or Degrade the Performance of Military Systems 18 p (SEE N91-18506 10-46)
Availability Source: CASI 

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