Simulated acoustic MPI system function in frequency space. At each position × of the infinitely small sample, the system response in the time domain is calculated and Fourier-transformed. Fourier-amplitudes are plotted for the first 3 harmonics. A value of 5 T μ0-1/m was assumed for the gradient strength G×, the drive field amplitude was set to 2.5 mT μ0-1, and a particle diameter of 17 nm was assumed. Figure 1 - One-dimensional signal generation in MPI.