Global modeling of equatorial spread F with SAMI3/WACCM-X

We report the first results of a global ionosphere/thermosphere simulation study that self-consistently generates large-scale equatorial spreadF(ESF) plasma bubbles in the postsunset ionosphere. The coupled model comprises the ionospheric code SAMI3 and the atmosphere/thermosphere code WACCM-X. Two cases are modeled for different seasons and geophysical conditions: the March case (low solar activity: F10.7 = 70) and the July case (high solar activity: F10.7 = 170). We find that equatorial plasma bubbles formed and penetrated into the topsideFlayer for the March case but not the July case. For the March case, a series of bubbles formed in the Atlantic sector with irregularity spacings in the range 400-1,200 km, rose to over 800 km, and persisted until after midnight. These results are consistent with recent GOLD observations. Calculation of the generalized Rayleigh-Taylor instability (GRTI) growth rate shows that the e-folding time was shorter for the March case than the July case.