Figure 2. The MFPT function 
of a Brownian particle in a disk with symmetrically located targets.
(as shown e.g. in Fig. 1a). Its values are plotted as a surface which depends on the particle's starting position 
in the bottom plane of each figure. The surface colour is added only to clarify points of a large MFPT (red shading) against a small MFPT (blue shading). In the top row 
is computed for the ‘fast’ model in which 
= 0.5 
m, 
m
/s and 
= 150 Å, with 
, 20 and 50, correspondingly, respectively, to panel A, B and C. The bottom row shows the results for the ‘slow’ model in which 
= 0.5 
m, 
m
/s and 
= 15 Å, and with 
, 20 and 50, correspondingly, respectively, to panel D, E and F.