Can Throat Auroras Create Polar Cap Patches？

<p>Throat auroras and polar cap patches are common phenomena in the polar ionosphere. An observation campaign was organized, with all-sky imagers at Yellow River Station in Ny-&#197;lesund in Svalbard, the EISCAT Svalbard Radar, and coordinated low-altitude spacecraft observations. During periods of radial interplanetary magnetic field (IMF), observations showed that poleward moving throat auroras were linked to poleward moving ionization patches. Throat auroras are produced by soft-electron precipitation associated with dayside magnetic reconnection. The red line intensity of throat auroras is found to be correlated with dayside reconnection events. Dense plasma from lower latitudes was transported poleward by enhanced convection associated with the throat auroras to form electron density patches. This is potentially a new patch formation mechanism that is associated with throat auroras and magnetic reconnection for radial IMF. Moreover, the patches were found to E &#215; B drift in the anti-sunward direction.</p>