A Unique Combination of Equatorial Plasma Bubble Morphologies Occurring
Within a 12 deg Longitude Range
Abstract
On 12 October 2020, the NASA’s Global-scale Observations of the Limb and
Disk (GOLD) mission observed three differently shaped EPBs within a
12o longitude range, near the subsatellite point. One
is straight aligned to the magnetic field line, whereas the poleward
extensions of the others are tilted eastward and westward from the
magnetic field line resembling a C-shape and reversed C-shape
structures. These EPBs were inside the GOLD imager’s field-of-view for a
period of ~3 hours. This allowed us to compute their
zonal motion and determine their drift velocities. EPBs’ drift
velocities were derived from measuring their longitudinal shifts at the
magnetic equator and at both EIA crests. This unique observation,
showing three morphologies in a narrow longitude sector, indicates the
occurrence of strong longitudinal gradients in the typical parameters
associated with the dynamics of EPBs, like neutral winds, electric
fields, or other parameters within such a narrow longitude range.