Harmonic Generation of Microwave Phonons by Radiation Pressure and by the Phonon Phonon Interaction
Paul H. Carr · 1966
This 1966 research revealed fundamental mechanisms of how microwave radiation transfers energy into matter through molecular vibrations.
Plain English Summary
This 1966 technical report examined how microwave radiation generates harmonic phonons (sound waves at the atomic level) through radiation pressure and phonon interactions. The research explored the fundamental physics of how microwave energy transfers into matter at the molecular scale. This work helped establish early understanding of how microwave radiation interacts with biological materials.
Why This Matters
While this 1966 research predates modern EMF health concerns, it represents crucial foundational science for understanding how microwave radiation interacts with matter at the molecular level. The study of phonon generation by radiation pressure helps explain the physical mechanisms by which microwave energy transfers into biological tissues. This isn't just academic physics - it's the underlying science that explains how your microwave oven heats food and how cell phone radiation deposits energy in your body.
What makes this research particularly relevant today is that it examined the fundamental energy transfer mechanisms that occur when microwave radiation encounters any material, including human tissue. The phonon interactions described in this work represent the initial steps in the cascade of biological effects that can result from microwave exposure. Understanding these basic physics principles helps explain why microwave radiation has biological effects beyond simple heating.
Finding
The conversion of power from the 4.5GHz fundamental of a longitudinal wave along the (100) axis of MgO to the second harmonic has been observed to be as large as 60 percent. This strong interaction was shown to be due to the nonlinearity of the elastic medium or the phonon phonon interaction.
In their words
“The conversion of power from the 4.5GHz fundamental of a longitudinal wave along the (100) axis of MgO to the second harmonic has been observed to be as large as 60 percent. This strong interaction was shown to be due to the nonlinearity of the elastic medium or the phonon phonon interaction.”
Figures from the Original Paper
Diagrams extracted from the original research document.
Exposure Information
Specific exposure levels were not quantified in this study.
Study Details
To present measurement of two different physical processes for harmonically generating microwave phonons: radiation pressure and the phonon phonon interaction.
Sound waves are generated by radiation pressure at the end surface of a nonpiezoelectric Z-cut quart...
The measured strain amplitude was computed from the magnitude of the detected acoustic power P,, by ...
The radiation pressure generation mechanism was established by the quantitative agreement between the predicted sonic power generated and the detected power. The conversion of power from the 4.5GHz fundamental of a longitudinal wave along the (100) axis of MgO to the second harmonic has been observed to be as large as 60 percent. This strong interaction was shown to be due to the nonlinearity of the elastic medium or the phonon phonon interaction. The coupling constant for the interaction |F| was measured to be 21 + 10 and was related to the third-order elastic constant c111 = -63 + 26 X 10"" dynes/cm?. A solution of the nonlinear wave equation in a lossy medium has been made.
Show BibTeX
@article{harmonic_generation_of_microwave_phonons_by_radiation_pressure_and_by_the_phonon_g5527,
author = {Paul H. Carr},
title = {Harmonic Generation of Microwave Phonons by Radiation Pressure and by the Phonon Phonon Interaction},
year = {1966},
}