  We solve the infinite-dimensional stochastic differential equations (ISDEs)
describing an infinite number of Brownian particles in $ \mathbb{R}^+$
interacting through the two-dimensional Coulomb potential. The equilibrium
states of the associated unlabeled stochastic dynamics are Bessel random point
fields. To solve these ISDEs, we calculate the logarithmic derivatives, and we
prove that the random point fields are quasi-Gibbsian.
