  We generalize an idea in the works of Landauer and Bennett on computations,
and Hill's in chemical kinetics, to emphasize the importance of kinetic cycles
in mesoscopic nonequilibrium thermodynamics (NET). For continuous stochastic
systems, a NET in phase space is formulated in terms of cycle affinity
$\nabla\wedge\big(\mathbf{D}^{-1}\mathbf{b}\big)$ and vorticity potential
$\mathbf{A}(\mathbf{x})$ of the stationary flux
$\mathbf{J}^{*}=\nabla\times\mathbf{A}$. Each bivectorial cycle couples two
transport processes represented by vectors and gives rise to Onsager's
reciprocality; the scalar product of the two bivectors
$\mathbf{A}\cdot\nabla\wedge\big(\mathbf{D}^{-1}\mathbf{b}\big)$ is the rate of
local entropy production in the nonequilibrium steady state. An Onsager
operator that maps vorticity to cycle affinity is introduced.
