polar cap

n.

行星两极处之极冠，南北极的冰帽；

Polar cap
Polar cap
Magnetic activity in the polar cap—A new index
Variations in the polar cap area during two substorm cycles
F layer ionization patches in the polar cap
Dependence of polar cap potential drop on interplanetary parameters
Polar cap electric field structures with a northward interplanetary magnetic field
Gamma-Ray Pulsars: Emission from Extended Polar CAP Cascades
A new source of suprathermal O + ions near the dayside polar cap boundary
Electric and magnetic field characteristics of discrete arcs in the polar cap