@article{MoutalGrebenkov2020, author = {Moutal, Nicolas and Grebenkov, Denis S.}, title = {The localization regime in a nutshell}, series = {Journal of magnetic resonance : JMR}, volume = {320}, journal = {Journal of magnetic resonance : JMR}, publisher = {Elsevier}, address = {San Diego, Calif. [u.a.]}, issn = {1090-7807}, doi = {10.1016/j.jmr.2020.106836}, pages = {11}, year = {2020}, abstract = {High diffusion-sensitizing magnetic field gradients have been more and more often applied nowadays to achieve a better characterization of the microstructure. As the resulting spin-echo signal significantly deviates from the conventional Gaussian form, various models have been employed to interpret these deviations and to relate them with the microstructural properties of a sample. In this paper, we argue that the non-Gaussian behavior of the signal is a generic universal feature of the Bloch-Torrey equation. We provide a simple yet rigorous description of the localization regime emerging at high extended gradients and identify its origin as a symmetry breaking at the reflecting boundary. We compare the consequent non-Gaussian signal decay to other diffusion NMR regimes such as slow-diffusion, motional-narrowing and diffusion-diffraction regimes. We emphasize limitations of conventional perturbative techniques and advocate for non-perturbative approaches which may pave a way to new imaging modalities in this field.}, language = {en} }