Upper hybrid oscillations involvelongitudinal motions of electrons perpendicular to the magnetic field. Theupper hybrid frequency, ΦUH, is governed bythe relationshipΦUH^
2 =Φpe^2 +Θce^2 whereΦpe is electron plasma frequency andΘce is the electron cyclotron frequency.
The mantle is divided into sections based upon results from seismology. The upper mantle is the region from 33–410 km (20 to 254 miles). The upper part of the mantle is composed mostly of peridotite,
a rock denser than rocks common in the overlying crust. [Wikipedia]
The uppermost mantle plus overlying crust are relatively rigid and form the lithosphere, an irregular layer with a maximum thickness of perhaps 200 km. [Wikipedia]