The principles of developing the ball lightning theory

Criteria for developing the ball lightning theory based on the results of observations are analyzed. It is assumed that the key features of ball lightning are a large energy (more than 10(6) J) and long lifetime (more than 1 s). We exclude from consideration theories which do not explain these features and concentrate our attention on the analysis of three models where the large energy, of the autonomous ball lightning and the forces providing the compression of the ball lightning substance are taken into account. The first considered model was developed by Geert Dijkhuis, in which the appearance of a force directed towards the system center is attributed to the Bose condensation of vortices of degenerated electrons as well as to gradient forces arising due to a nonuniform distribution of the electron density over the ball lightning volume. The second model proposed by Vladimir Bychkov assumed that the energy reservoir of ball lightning is polymer threads carrying a big electric charge. Our model assumes that the energy is stored in the form of kinetic energy of ions which the positively charged core of ball lightning is thought to consist of. The core is compressed by a dielectric shell which, in turn, is shrunk by the force created due to the nonuniform electric field of the core. The merits and limitations of these and other models are discussed.