Problem

Modify your program from Problem 1 to use a diffusivity of size $a = 0.001$ and compute with the same time step until time $T = 20$. Compare to your solution in Problem 1. Can you explain the difference? What happens when we decrease the diffusion?

Check your answer: Compare your solution with a reference solution using the commands load solution2 and then makemovie. This solution has been computed on a finer mesh (square_refined.m) with a time step of size $k = 0.1$ and $T = 20$.