Value chain · CLM-0067
In plain terms
According to a 2007 international report, Japanese designs of the time chose their beam strength on cost and land grounds; the report does not give the ionosphere as the reason.
The claim as recorded
No source found cites an ionospheric constraint as the basis for a Japanese design's chosen beam intensity: the Report of the URSI Inter-Commission Working Group on SPS, attached to but separate from its White Paper, states that current designs have opted for larger transmitting antennas and smaller rectenna sites, but a larger power density on the ground to conserve land use, especially in Japan, and that the maximum power density depends on the antenna size and the frequency, which directly affect the total cost.
Scope and limits
Establishes the stated basis in the sources found, not the internal reasoning of either programme. The underlying Japanese-language JAXA document behind the URSI table, its footnote 37, was not traced. A CAST-led 2024 concept paper models a peak ground power density of about 460 W/m2 at 5.8 GHz (SRC-169 PDF p.8, CLM-0501) and never mentions the ionosphere (CLM-0142). No power density figure was found for the Chongqing Bishan test base, and the basis of a Chinese demonstrator's beam intensity is not claimed here, because the Chinese-language reports on it (Chinese Academy of Sciences, 2022; China Daily Shaanxi, 2026) are not held. SRC-113 PDF p6, for a different ground prototype, says only that peak density outside the receiving antenna should be below the value in national standards.
What it assumes
No assumptions are recorded against this claim.
Where it comes from
Report, PDF p176 (printed p155): "it can be seen from the table that current designs have opted for larger transmitting antennas and smaller rectenna sites, but a larger power density on the ground to conserve land use, especially in Japan." PDF p179 (printed p158), section 4.3: "The maximum power density depends on the antenna size and the frequency, which directly affect the total cost." Table 2.3.2 is at PDF p95 (printed p74).
Related records
- Answers question
- QST-001 not published in this releaseQST-006 not published in this release
Cite this
energyaperture.com/c/clm-0067
CLM-0067, 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-0047Heating falls with the square of frequency. In 2007 no ground-based measurement of it was available at gigahertz frequencies, and...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-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.