We study the thermodynamics and phase structure of asymptotically flat
non-dilatonic as well as dilatonic black branes in a cavity in arbitrary
dimensions (D). We consider the canonical ensemble and so the charge inside
the cavity and the temperature at the wall are fixed. We analyze the stability
of the black brane equilibrium states and derive the phase structures. For the
zero charge case we find an analog of Hawking-Page phase transition for these
black branes in arbitrary dimensions. When the charge is non-zero, we find that
below a critical value of the charge, the phase diagram has a line of
first-order phase transition in a certain range of temperatures which ends up
at a second order phase transition point (critical point) as the charge attains
the critical value. We calculate the critical exponents at that critical point.
Although our discussion is mainly concerned with the non-dilatonic branes, we
show how it easily carries over to the dilatonic branes as well.Comment: 37 pages, 6 figures, the validity of using the effective action
discussed, references adde