Value chain · CLM-0108
In plain terms
A 2004 ESA review found that during the October 2003 solar storm, just under 20 per cent of a space solar power beam would have been absorbed before reaching the ground. In quiet conditions the loss is under 0.3 per cent.
The claim as recorded
A 2004 ESA review computes collisional absorption of a 2.48 GHz space solar power beam and reports that under normal conditions over 99.7 per cent of the power remains after traversing the entire ionosphere and atmosphere, that using a measured extreme electron density profile from the EISCAT radar during the late October 2003 coronal mass ejection only just over 80 per cent of the beam power reaches ground level, and that even under the most extreme lightning conditions no more than about 3 per cent of the power is lost.
Scope and limits
The CME figure is MODELLED, using the same non-deviative absorption relation used in CALC-013, but its density input is a MEASURED EISCAT profile, so it is a model driven by real disturbed-ionosphere data rather than by an assumed profile. It is one extreme profile from one event, not a distribution. The review states the beam frequency as 2.48 GHz. No elevation angle is stated. SRC-104 page 7 also notes "most of the absorption takes place in the lower ionosphere", which agrees with CALC-013's finding that the D and E regions dominate.
What it assumes
No assumptions are recorded against this claim.
Where it comes from
page 7: "Under normal conditions, i.e. in the absence of geomagnetic and solar disturbances, the absorption effects on the SPS beam would be expected to be extremely small. Using the electron density and collision frequency input data in Fig. 1 it is clear from Fig. 2 (dashed curve) that over 99.7% of SPS microwave power remains after traversing the entire ionosphere and atmosphere." Page 8: "Using one of the extreme density profiles from the EISCAT radar, illustrated in Fig. 1, the absorption levels for a 2.48 GHz signal were recalculated. The absorption levels under the enhanced conditions were now found to be significant, with only just over 80% of the SPS beam power reaching ground level". Page 8 on lightning: "even under the most extreme conditions associated with lightning, it is estimated that no more than about 3% of the power is lost due to these effects."
Related records
- Answers question
- QST-009 not published in this release
- Contradicts
- CLM-0107 not published in this release
- Supersedes
- CLM-0107 not published in this release
Cite this
energyaperture.com/c/clm-0108
CLM-0108, Energy Aperture, as of 2004.
Connected records
Other published records linked to this one. A list, not a judgement.
- Also from SRC-104
- CLM-0042The 230 watts per square metre figure applies to one frequency and one design lineage. Japanese designs at a higher frequency allow up to...CLM-0057There is a formula for the instability threshold. It depends on electron density cubed, electron temperature to the fourth power, and...CLM-0059The two fields were largely the same people from the 1970s, and papers linking them were still appearing after 1991.CLM-0075When ESA revisited the question in 2004 it used the 1978 theory and did not cite the 1979-81 Platteville tests or NASA's 1981 revision 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-0109In normal conditions the ionosphere takes essentially none of the beam. In a severe solar storm it could take a little under a fifth of it.CLM-0130The quiet-condition absorption figures from four sources do not disagree. One of them states an upper bound and the others sit inside it.More on the source page.