A fast algorithm for computing the pulsed-gradient spin-echo signal
in multiscale porous media

D. S. Grebenkov

Laboratoire de Physique de la Matiere Condensee,
CNRS -- Ecole Polytechnique, F-91128 Palaiseau, France

Email: denis.grebenkov@polytechnique.edu

A reliable interpretation of pulsed-gradient spin-echo (PGSE)
experiments in mineral samples and biological structures such 
as concrete, sedimentary rocks or lungs, requires intensive 
numerical studies of restricted diffusion.  Classical Monte 
Carlo simulations with a fixed time step are too long and 
inefficient in such porous media. I propose a fast algorithm 
for computing the PGSE signal in multiscale structures. The 
algorithm relies on random walks with variable jumps which are 
adapted to local geometrical length scales. An implementation 
of gradient encoding is a new feature that opens a possibility 
for efficient and accurate numerical simulations in model and
reconstructed three-dimensional porous media.


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