To the 2D Electric Structure of the Fog
The problem of fog particles charging and electric field vertical profile is considered. The 2D approach has been used, that is allowed for almost all fog systems. The fixed height fog layer with poly-disperse water droplets with given concentration, Nq, is used as a bulk model. All particles are flowing down in the Earth gravity field and under the external electric field, E0. Due to the bipolarion environment, each particle acquires charge with the rate, determined by the diffusion mechanism of charging 1,3. In earlier works, aerosols in the boundary layer were considered as heavy ions with fixed charge (=e, elementary charge) and no charging processes were taken into account 2. The system is considered as five-component: neutral molecules, heavy ions or condensation nuclei, light ions, poly-disperse fog particles.The steady homogeneous state of the fog particle and atmospheric ions system has been analytically and numerically investigated. It leads to reducing of ion equilibrium concentration, ni0, is connected with the growth of parameter ε q=qTNq/en0, where qT =Ti R/e is the thermal charge, Ti is the ion temperature in energy units, n0 is the equilibrium ion concentration in the absence of the fog and electrode effect. The presence of the Earth leads to forming of inhomogeneous stationary electric field and net charge profile with positive charge domination near the ground 2. The character scale of this positive layer is about E0/4 π en0 in the absence of turbulence. The presence of fog particles and heavy ions produces the electric field and space charge growth near the ground, if we assume that electric field over the fog layer is fixed 4. It means, in other words, that the total current density (ion drift current + all particles sedimentation current) is the same as under the fair weather conditions. Under the opposite case, when electric field on the Earth surface is fixed, the calculation gives the reducing space charge on ground level when parameter ε q is growing up. The transition 2D case is also investigated numerically; the electric field data has been obtained till the 60 km height above the fog top. 1 N.A. Fuchs, To charge magnitudes on atmospheric air-colloids, Izv. Academy of Science USSR, geography and geophysics series, v.11, N4, pp. 341-347, 1947.2 W.A. Hoppel, Theory of the electrode effect, J. Atmospheric and Terrestrial Physics, v.29, pp.709-721, 1967.3 W.A. Hoppel, G.M. Frick, Ion-aerosol attachment coefficient and the steady-state charge distribution on aerosols in a bipolar ion environment, J. Aerosol Science and Technology, v.5, pp. 1-21, 1986.4 S.V. Anisimov, E.A. Mareev, A.E. Sorokin, N.M. Shikhova, E.M. Dmitriev, Electrical Properties of Fog, Izvestiya, Atmospheric and Oceanic Physics, pp. 51-64, v.39, N1, 2003.
Andrei E. Sorokin
Institute of Applied Physics RAS, Nizhny Novgorod, Russia
国际会议
第13届国际大气电学会议(The 13th International Conference on Atmospheric Electricity)
北京
英文
2007-08-13（万方平台首次上网日期，不代表论文的发表时间）