When the surface of a body is subjected to transient heating (e.g., by electron bombardment or rf absorption) elastic waves are produced as a result of surface motion due to thermal expansion. This process is analyzed, with particular emphasis on the case of an input heat flux varying harmonically with time, to relate the elastic wave amplitude to the characteristics of the input flux and the thermal and elastic properties of the body. Experiments performed with both electron impact and rf absorption verify the proportionality of the stress wave amplitude and the absorbed power density, and correlate well with the thermal and elastic properties of the heated medium. Comparison of the elastic wave stress amplitude with radiation pressure shows that the former may be much greater than the latter, as experiments have demonstrated. When a barium titanate crystal was used to detect the elastic waves produced, heating by a single 2‐μsec pulse of electrons or microwave radiation produced easily detectible signal...
[1]
A. Love,et al.
The Mathematical Theory of Elasticity.
,
1928
.
[2]
J. C. Jaeger,et al.
Conduction of Heat in Solids
,
1952
.
[3]
Ian Naismith Sneddon,et al.
The generation of waves in an infinite elastic solid by variable body forces
,
1956,
Philosophical Transactions of the Royal Society of London. Series A, Mathematical and Physical Sciences.
[4]
M. De.
Handbuch der Physik
,
1957
.
[5]
Alex Grumet.
Penetration of Transient Electromagnetic Fields into a Conductor
,
1959
.
[6]
Thermal impact—the mechanical response of solids to extreme electromagnetic radiation
,
1961
.
[7]
An Elastic Wave Method for the Measurement of Pulse-Power Density
,
1962
.
[8]
Richard M. White,et al.
Elastic Wave Generation by Electron Bombardment or Electromagnetic Wave Absorption
,
1963
.