Multi-scale behavior of Langmuir turbulence during ionospheric heating experiments

We present new results of multi-scale simulations of Langmuir turbulence during heating experiments where a powerful electromagnetic wave is injected into the overhead ionosphere where it excites parametric instabilities leading to turbulence on multiple spatial and temporal scales. The simulations are carried out using a generalized Zakharov model [1, 2] in which the complex phase and amplitude of the high-frequency electromagnetic and electrostatic waves are solved using an implicit method, and are coupled to ion fluctuations via the ponderomotive force acting on the electrons, which pull the ions via the space charge electric field. The 3-wave parametric decay instability (PDI) and 4-wave oscillating two-stream instability (OTSI) lead to strong Langmuir turbulence with nucleation and burn-out cycles of localized Langmuir wave packets trapped in ion density cavities.