Value chain · CLM-0114
In plain terms
The Russian treatment says self-focusing is triggered by lumpiness already present in the ionosphere, not by beam power crossing a line. That lumpiness is almost always there, so in practice the threshold nearly always is met.
The claim as recorded
The Soviet treatment of the self-focusing instability sets its threshold on a PRE-EXISTING ambient electron density perturbation of order 1e-4 to 1e-5 of ambient density rather than on incident wave power, states that perturbations of that size frequently exist in the ionosphere under natural conditions, notes that the formal threshold shrinks continuously as wave power rises rather than jumping discontinuously, and describes the growth as explosive in character once triggered.
Scope and limits
This is HF-resonant physics, evaluated at plasma-resonance heights, not microwave transmission through an underdense ionosphere. The two regimes are physically different and this must not be read as a statement about a 2.45 GHz power beam. It bears on the CONCEPT of a threshold, not on the value of one.
What it assumes
No assumptions are recorded against this claim.
Where it comes from
pages 95-96. The threshold perturbation is 0.01 to 0.001 per cent of ambient density, and real ionospheric plasma almost always already carries irregularities above it. The formal threshold enters through 1 over the square of the wave field, so it shrinks continuously with rising power. Verbatim on growth: "the resonant instability has an explosive character. Therefore the characteristic time of the nonstationary processes decreases sharply if the perturbation greatly exceeds (in absolute value) the threshold perturbation."
Related records
- Answers question
- QST-001 not published in this release
Cite this
energyaperture.com/c/clm-0114
CLM-0114, Energy Aperture, as of 1975.
Connected records
Other published records linked to this one. A list, not a judgement.
- Also from SRC-132
- CLM-0116The Russian formulas are a different shape from the 0.43 relation, so they cannot be used to check it either way.CLM-0147A major 2007 physics review gives a different mathematical formula, with different dependence on temperature and frequency and no...CLM-0158Neither of the two sources read at the page, a 2004 review by Robinson and others and Gurevich (2007), states the range of conditions under...
- Also from SRC-133
- CLM-0115The Russian and American researchers were talking to each other from at least 1974, so they are not two fully independent traditions.CLM-0116The Russian formulas are a different shape from the 0.43 relation, so they cannot be used to check it either way.CLM-0146A 1975 Soviet theory paper calculated an exact minimum radio-wave strength - about 300 millivolts per metre in daytime, ten times less at...