530 Physik
Filtern
Volltext vorhanden
- nein (1)
Erscheinungsjahr
- 2020 (1) (entfernen)
Dokumenttyp
Sprache
- Englisch (1)
Gehört zur Bibliographie
- ja (1)
Schlagworte
- Bloch-Torrey equation (1)
- Diffusion NMR (1)
- Localization regime (1)
- Non-perturbative analysis (1)
- Spin-echo (1)
Institut
- Institut für Physik und Astronomie (1) (entfernen)
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.