Three‐dimensional equatorial spread F modeling: Zonal neutral wind effects

The NRL SAMI3/ESF three‐dimensional simulation code is used to examine the effect of zonal neutral winds on the dynamics and morphology of equatorial spread F (ESF). Three zonal wind models are used: (a) a constant eastward neutral wind of 150 m/s, (b) HWM93, and (c) HWM07. It is shown that the dynamics and morphology of the ESF bubbles depends strongly on the zonal neutral wind. The simulation results are compared with TIMED/GUVI and IMAGE/FUV data. For the conditions studied (F10.7 = 170) it is found that the HWM93 wind model results agree better with the data than those from a constant wind model or HWM07. Specifically, observations of a reversed ‘C’ shaped FUV image, a westward tilt of the plasma bubble, and a decrease in zonal bubble velocity with increasing latitude are reproduced by SAMI3/ESF.