Panel a: plasma inflow (green arrows) and outflow (black arrows) directions in a magnetic islands chain. The solid orange lines show the magnetic field in the x−z plane. Here islands “1” and “2” represent the squashed islands, while islands “3” and “4” represent the coalescent islands. Panel b: red dash-dot line shows the E_y from squashed islands on the midplane from Eq. (17). The blue dash line shows the E_y from coalescent islands on the midplane from Eq. (18). Here k = 0.03125.