Temperature oscillations in liquid media caused by continuous (nonmodulated) millimeter wavelength electromagnetic irradiation.
Convection in liquids caused by 53-78 GHz millimeter wave irradiation with incident power density that ranged from 10 microW/cm2 to 1 W/cm2 was studied. Infrared thermography was used as an artifact-free method for recording surface-temperature dynamics during irradiation. It was found that continuous (nonmodulated) waves can produce a relaxation-type temperature oscillation in liquids with a relatively high stability of the period between temperature spikes. The temperature oscillation is due to the repetitive formation and dissipation of a torroidal type of convection vortex. When the vortex became stable during irradiation, we observed a temperature decrease following the initial temperature-rise phase, even though the irradiation was constantly maintained. This result constitutes a new process that can play a significant role in producing microwave bioeffects, including some so-called "nonthermal" effects and some effects that are inversely related to heating. Also, it can be considered as a newly discovered potential artifact in microwave bioeffects studies.
Khizhnyak
E P
EP
Institute of Cell Biophysics, Russian Academy of Sciences, Pushchino, Moscow Region, Russia.
Ziskin
M C
MC
D055592:Biophysical Phenomena; D001703:Biophysics; D055590:Electromagnetic Phenomena; D006358:Hot Temperature; D008872:Microwaves / Q000009:adverse effects; D013696:Temperature; D014867:Water
D014867:Water