Ionospheric plasma irregularities inside the mid-latitude trough by using Swarm observations

<p>The mid-latitude ionospheric trough (MIT) is a well-known feature in the topside ionosphere and plasmasphere. In this report,&#160;we&#160;investigated&#160;the plasma irregularities inside the MIT region&#160;based on the high-resolution (2 Hz) measurements of electron density and temperature from the Swarm satellite. We developed a method to&#160;automatically&#160;identify the mid-latitude trough from Swarm in-situ density measurements, and&#160;the small-scale irregularities inside MIT region can also be well determined by considering appropriate thresholds of&#160;both the relative (&#8710;Ne/Ne) and&#160;absolute (&#8710;Ne) density fluctuations. Further statistics has been performed&#160;based-on the multi-years database of identified MITs and irregularities from Swarm. Finally, we&#160;provided for the first time the seasonal and magnetic local time distributions of irregularities within the MIT region, and the involved plasma instabilities&#160;that cause&#160;the irregularities&#160;at the MIT region have been discussed.</p>