The processes of molecular-nitrogen dissociation in the upper atmosphere
of Titan are an important source of suprathermal nitrogen atoms. The
dissociation-produced nitrogen atoms are characterized by an excess of
kinetic energy and, accordingly, play an important role in the dynamical
processes of the hot nitrogen- corona formation and of nonthermal escape
of gas to Saturn's magnetosphere. This study is based on a detailed
investigation of the kinetics of suprathermal-nitrogen-atom production
through the processes of dissociation and dissociative ionization of
molecular nitrogen by hard solar UV radiation and by the accompanying
flux of high-energy photoelectrons (Shematovich, 1998). On the basis of
a stochastic-simulation method, a numerical solution is obtained to the
Boltzmann equations for the transport and the collisional kinetics of
suprathermal nitrogen atoms in the ground state and in an electronic
excitation state in Titan's upper atmosphere. In this way, steady-state
nonequilibrium kinetic-energy distribution functions are calculated for
the thermosphere-exosphere transition region. From these
characteristics, the role of the processes of molecular-nitrogen
dissociation in the formation of Titan's hot nitrogen corona is
estimated, as well as the contribution of these processes to the flux
of nitrogen atoms escaping Titan's atmosphere.