Measuring ion temperatures and studying the ion energy balance in the high-latitude ionosphere

摘要: Abstract Data are presented for a nighttime ion heating event observed by the EISCAT radar on 16 December 1988. In experiment, aspect angle between beam and geomagnetic field was fixed at 54.7°, which avoids any ambiguity in derived temperature caused anisotropy velocity distribution function. The data were analyzed with an algorithm takes account of non-Maxwellian line-of-sight distribution. During event, spectral distortion parameter ( D ∗ ) indicated that function highly distorted from Maxwellian form when drift increased to 4 km s −1 . true three-dimensional used simplified balance equation compute mass during event. composition found change predominantly O mainly molecular ions. A theoretical analysis composition, using MSIS86 model published values chemical rate coefficients, accounts order-of-magnitude increase atomic/molecular ratio but does not successfully explain very high proportion ions observed.