  This paper is concerned with the concepts of regional controllability for the
Riemann-Liouville time fractional diffusion systems of order $\alpha\in(0,1)$.
The characterizations of strategic actuators to achieve regional
controllability are investigated when the control inputs emerge in the
differential equations as distributed inputs. In the end, an approach to
guarantee the regional controllability of the problems under consideration in
the considered subregion with minimum energy control is described and
successfully tested through two applications.
