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

Abstract:

We report results from a global ionosphere/thermosphere simulation study that self-consistently generates large-scale equatorial spread $F$ (ESF) plasma bubbles in the post-sunset ionosphere. The coupled model comprises the ionospheric code SAMI3 and the atmosphere/thermosphere codes WACCM-X and HIAMCM. An important feature of the study is that a high resolution grid is used globally with scale sizes of 70 km. Several cases are studied for different seasons and solar activity. In addition to seasonal and solar activity variations in the onset of ESF, we also find a strong longitudinal variation. The bubbles are initiated self-consistently by atmospheric gravity waves in the WACCM-X and HIAMCM models. Additionally, in one simulation we found a series of bubbles formed in the Atlantic sector with irregularity spacings in the range 400 - 1200 km, rose to over 800 km, and persisted until after midnight. These results are consistent with recent GOLD observations (shown in attached figure).