Asymmetric Development of Equatorial Plasma Bubbles Observed at Geomagnetically Conjugate Points Over the Brazilian Sector

Abstract

AbstractGround‐based global navigation satellite systems (GNSS) receivers have been used to monitor the meridional (north‐south) development of equatorial plasma bubbles (EPBs) at geomagnetically conjugate points over the Brazilian sector. EPBs were studied using detrended total electron content plots obtained from Boa Vista (MLat: 9.6°N), Itacoatiara (MLat: 3.3°N), Colíder (MLat: 5.0°S), and Cuiabá (MLat: 8.8°S) GNSS receivers. All GNSS receivers are located approximately under the same magnetic meridian. 655 nights with EPBs occurrence were analyzed using data from January 2012 to February 2016. In 459 nights (∼70%) the EPBs presented a symmetric development with respect to the geomagnetic equator. However, in 196 nights (∼30%) the EPBs presented an apparent asymmetry. The asymmetries are characterized as a displacement of the EPBs to north (or south) of the geomagnetic equator. The highest north (south) asymmetry occurrence was observed during December to January (March to April and September to October), and lowest during March to April and August to September (December to January). To investigate these asymmetries, we analyzed meridional wind data and used a numerical model to simulate the EPBs evolution. Both meridional wind data and numerical simulation results suggested that a trans‐equatorial meridional wind blowing to north (south) would be able to cause a displacement of the EPBs to north (south) of the geomagnetic equator.