Thin ion layers in the high-latitude lower ionosphere

摘要: Abstract Thin ion layers in the high-latitude lower ionosphere can be produced by action of wind-shears and electric fields on metallic other ions and, perhaps, processes. Modelling studies have been used to study two former mechanisms it has found that field effects will usually dominate those winds at auroral latitudes, producing altitudes as low 90 km. When are very small, however, should tidal or gravity waves, they latitudes. A considerable number observations thin made during 10 years operation EISCAT incoherent scatter radar. Most, but not all, these likely composed ions. Many fit well with model calculations formation action, others better explained a result wind shear. The average seasonal daily variations occurrence frequency altitude distribution combination fields. However, puzzling features still remain unexplained, for example correlation neutral atoms extreme thinness some layers. successes failures theories their discussed.