Electric current generated by ultrasonically induced Lorentz force in biological media |
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Authors: | Dr A Montalibet J Jossinet A Matias D Cathignol |
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Institution: | (1) National Institute for Health and Medical Research, Lyon, France |
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Abstract: | The ions of solutions exposed to the propagation of ultrasound in the presence of a magnetic field experience Lorentz force.
Their movement gives rise to a local electric current density, which is proportional to the electric conductivity of the medium.
In vitro assessment of this current is performed using simple models of biological media. A constant magnetic field of 0.35T
and 500kHz pulsed ultrasound are used. The sensing electrodes are exposed to neither the pressure wave nor the magnetic field,
thus ensuring that the signal is not due to any undesirable electrode effect. The experimental results confirm that the current
is proportional to the electrical conductivity of the medium. The changes in the measured current against the width of the
measurement chamber show that the electrodes only collect fraction of the current created within the medium. The magnitude
of the measured current is 50nA in a saline solution of 0.5S/m conductivity. The technique enabled the determination of the
conductivity of a porcine blood sample against haematocrit. It is concluded that this type of measurement has the potential
to allow the electrical conductivity of a medium to be determined using ultrasound. |
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Keywords: | Ultrasound Magnetic field Electric conductivity Current density Electrolyte |
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