Value chain · CLM-0047
In plain terms
Heating falls with the square of frequency. In 2007 no ground-based measurement of it was available at gigahertz frequencies, and theoretical estimates at 3 gigahertz said a rise in electron temperature from 200 K to 1000 K in the E layer might occur at 500 watts per square metre.
The claim as recorded
The URSI White Paper states that ionospheric ohmic heating is assumed small above 1 GHz because heating efficiency varies as the inverse square of frequency, that no ground-based measurements of electron heating by high-power microwaves exist in the GHz range, and that only theoretical estimates exist for 3 GHz, indicating an E-layer electron temperature rise from 200 K to 1000 K might occur at a power-flux density of 500 W/m2.
Scope and limits
URSI reference [43] is not yet identified and is probably Perkins and Roble. The 500 W/m2 figure is a theoretical estimate at 3 GHz, not a measurement and not at 2.45 GHz. It states a temperature rise, not a damage threshold, and the two are not the same thing.
What it assumes
No assumptions are recorded against this claim.
Where it comes from
Verbatim: "the effect is assumed to be small for radio-wave frequencies above 1 GHz, since the heating efficiency varies as the inverse square of the frequency. No ground-based measurements of electron heating by high-power microwaves are available in the GHz range; only theoretical estimates exist for a frequency of 3 GHz [43]. These estimates indicate that an electron-temperature increase from 200 K to 1000 K in the E layer might occur for a power-flux density of 500 W/m2."
Related records
- Answers question
- QST-009 not published in this release
- Contradicts
- CLM-0062 By 1981 the theory was being revised to a steeper frequency dependence, which would raise the...
Cite this
energyaperture.com/c/clm-0047
CLM-0047, Energy Aperture, as of 2007-06.
Connected records
Other published records linked to this one. A list, not a judgement.
- Also from SRC-100
- CLM-0032In 2007 the international radio science union published a white paper saying that nobody had measured this heating effect from the ground...CLM-0048An international scientific body reviewed the proposed figures, found them ranging from 230 to 1,000 watts per square metre, and chose 300...CLM-0049The stated design intent in a 2007 URSI white paper is that the beam would be shaped to fall to 10 watts per square metre by the edge of...CLM-0067According to a 2007 international report, Japanese designs of the time chose their beam strength on cost and land grounds; the report does...CLM-0079The 1978 paper modelled both a ground facility and a satellite case, and its 500 watts per square metre figure is a power flux for a given...CLM-0083The formula is the right type but nobody has said how far it can be pushed, and at space solar power frequencies the wave is about 200...CLM-0101The 1978 contract required the researchers to report fixes if ionospheric disturbance pushed the pilot-beam phase error past 2 to 3...CLM-0137In four major space solar power studies from 1978 to 2007, none put a number on how much of the beam's energy would be lost if the beam...More on the source page.
- Contradicted by
- CLM-0062By 1981 the theory was being revised to a steeper frequency dependence, which would raise the permitted power density.