The interaction of open and closed field lines at coronal hole boundaries is widely accepted to be due to interchange magnetic reconnection .
To date , it is unclear how the boundaries vary on short timescales and at what velocity this occurs .
Here , we describe an automated boundary tracking method used to determine coronal hole boundary displacements on short timescales .
The boundary displacements were found to be isotropic and to have typical expansion/contraction speeds of \leq 2 km s ^ { -1 } , which indicate magnetic reconnection rates of \leq 3 \times 10 ^ { -3 } .
The observed displacements were used in conjunction with the interchange reconnection model to derive typical diffusion coefficients of \leq 3 \times 10 ^ { 13 } cm ^ { 2 } s ^ { -1 } .
These results are consistent with an interchange reconnection process in the low corona driven by the random granular motion of open and closed fields in the photosphere .