科研之友
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摘要
The accumulation of charges on cloud particles by the charge transfer of ions and attachment of electrons in the atmosphere of Venus is investigated in the present work. Three cloud layers between 45 and 70 km exist in the atmosphere of Venus. Ions and electrons are produced by the interaction of galactic cosmic rays with the neutral molecules. Ion to particle and electron to particle attachment coefficients are calculated. The charge balance equations include ion-ion recombination, ion-electron recombination, electron attachment to neutrals, electron detachment from negative ions, and attachment of electron and charge transfer from ions to particles. It is found that the ion concentrations are reduced by a maximum of a factor of 5 by charging of the particles, while the earlier studies showed a maximum reduction of about an order of magnitude due to the differences in the surface area of the particles. A similar result is observed in the calculation of electrical conductivity. Both monodisperse and polydisperse distribution of particles are considered. The conductivity was reduced by a factor of 3 when using the monodisperse distribution of particles, while the maximum reduction observed was a factor of 2 when using the polydisperse distribution. This result implies that the monodisperse particle distribution overestimates the effect of particles on the atmospheric conductivity. The ratio of negative to positive charges is found to be very large in the middle and upper cloud layers. The low abundance of the aerosols and high conductivity of the atmosphere appear to rule out lightning activity in the 40 to 70 km altitude region.
- 出版日期2009-4-17
