Ferrite core non-linearity in coils for magnetic neurostimulation

[摘要] The need to correctly predict the voltage across terminals of mm-sized coils, with ferrite core, to be employed for magnetic stimulation of the peripheral neural system is the motivation for this work. In such applications, which rely on a capacitive discharge on the coil to realise a transient voltage curve of duration and strength suitable for neural stimulation, the correct modelling of the non-linearity of the ferrite core is critical. A demonstration of how a finite-difference model of the considered coils, which include a model of the current-controlled inductance in the coil, can be used to correctly predict the time-domain voltage waveforms across the terminals of a test coil is presented. Five coils of different dimensions, loaded with ferrite cores, have been fabricated and tested: the measured magnitude and width of the induced pulse are within 10% of simulated values.

[学科分类] 肠胃与肝脏病学

[关键词] ferrites;neurophysiology;biomagnetism;bioelectric potentials;finite difference methods;coils;patient treatment;ferrite core nonlinearity;coils;magnetic neurostimulation;peripheral neural system;capacitive discharge;transient voltage curve;finite-difference model;current-controlled inductance;time-domain voltage waveforms;Fe3O4