Density Troughs in the Ionosphere Sustained by Transport Barriers

This study explores the relaxation and sustainability of densityirregularities and plasma flows in the Earth’s ionosphere. To do this, weuse a modified model of drift-wave turbulence known as the Hasegawa-Wakatanimodel. Similar to turbulent processes in laboratory plasmas, we explore apowerful mechanism that can reduce the turbulent plasma transport. Thismechanism is associated with the creation of ‘zonal flows,’ cutting acrossthe gradients of particle density and magnetic fields. They work effectivelyto minimize particles’ random movement and reduce the turbulence causingthis movement. The zonal flows create transport barriers in areas where thedensity gradient is steepest and where drift waves grow most vigorously. Thetransport barriers significantly delay the refill of low-density regionswith surrounding plasma. They also lead to changes in the electric potentialof the plasma and influence the movement of ions in the direction of themagnetic field. Our research investigates how these zonal flows aregenerated and how effectively they sustain density irregularities. We alsoexamine the spectral characteristics of turbulence in and around thesebarriers.