The second Sporadic E Experiment over Kyushu (SEEK-2) was carried outon 3 August 2002, during an active sporadic-E event that also showedquasi-periodic (QP) echoes.Two rockets were launched into the event from Kagoshima Space Center insouthern Japan 15 min apart.Both carried a suite of instruments, but the second rocket alsoreleased a trimethyl aluminum (TMA) trail to measure the neutral windsand turbulence structure.In a number of earlier measurements in similar conditions, large windsand shears that were either unstable or close to instability wereobserved in the altitude range where the ionization layer occurred.The SEEK-2 wind measurements showed similar vertical structure, but unlikeearlier experiments, there was a significant difference between theup-leg and down-leg wind profiles.In addition, wave or billow-like fluctuations were evident in theup-leg portion of the trail, whilethe lower portion of the down-leg trail was found to haveextremely strong turbulence that led to a rapid break-up of the trail.The large east-west gradient in the winds and the strong turbulencehave not been observed before.The wind profiles and shears, as well as the qualitative characteristicsof the strong turbulence are presented, along with a discussion ofthe implications of the dynamical features.Keywords. Ionosphere (Mid-latitude ionosphere; Ionosphericirregularities; Electric field and currents)
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