  We describe the implementation of kinetic solvers in 1d2v phase space using
adaptive Cartesian mesh. Spherical coordinates in velocity space are used to
simplify the Lorentz and Fokker-Planck collisional operators. The key
capabilities of the new solvers are illustrated for electron elastic
scattering, acceleration, continuous energy loss in collisions, and ionization
processes in weakly-ionized plasma. We have also implemented two-stream
approach to reduce computational cost for studies of gas breakdown dynamics in
the presence of runaway electrons. The benefits and limitations of the
non-split-phase-space method for kinetic solvers with adaptive mesh in phase
space are discussed.
