Currents Induced in a Human Being for Electromagnetic Fields 10 kHz-50 MHz.
UTAH UNIV RESEARCH INST SALT LAKE CITY
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The two tasks undertaken during the period of this project are 1. Development of a high resolution thermal model of the human leg and its use to estimate the temperature distribution as a result of the induced high current densities at radio frequencies. 2. Development of a high-resolution, anatomically-realistic, inhomogeneous model of man and its use to calculate the SAR and induced current distributions for frequencies to 100 MHz. We have previously shown 1,2 that vertically polarized incident plane waves are capable of inducing fairly significant RF currents in a free-standing human being. Foot currents were found to be proportional to the frequency of incident radiation for the frequency band 0-40 Mega Hz with values as high as 12.7 milli AVm measured for adult human volunteers at 40 MHz. Recognizing that the induced current is divided equally between the two legs on its way to the ground underneath, fairly high current densities result in the various cross sections of the leg with concommitant high rates of energy deposition SAR. In particular, due to the predominantly bony nature of the ankle cross section forcing the RF current to flow in an effective 9.5 cm2 cross section of the high conductivity tissues, very high current densities J and the resulting SARs are set up. These SARs are almost two orders of magnitude larger than the metabolic rates of the tissues and considerably in excess of the ANSI guideline of 8 Wkg for any 1 g of tissue.
- Stress Physiology
- Electromagnetic Pulses