Table 3.

Plasma-wave populations in the magnetospheric system

Type	Location	Properties	Typical period (s) or frequency (Hz)
ULF waves	Dipolar region	Driven by Kelvin–Helmholtz Driven by solar-wind compressions Driven by ion plasma sheet Produce radial diffusion of electron radiation belt Energize radiation belt	100–600 s
Electromagnetic ion-cyclotron waves (EMIC)	Dipolar region inside plasmasphere and plume	Driven by ion plasma sheet Scatter plasma-sheet ions and radiation-belt electrons into atmosphere	0.2–5 s
Whistler-mode chorus waves	Dipolar region outside of plasmasphere	Driven by substorm-injected electrons Energize the electron radiation belt Scatter plasma-sheet and radiation-belt electrons into atmosphere Produce diffuse aurora	100–5000 Hz
Whistler-mode hiss waves	Dipolar region inside plasmasphere and plume	Driven by electron plasma sheet? Scatter radiation-belt electrons into atmosphere	100–5000 Hz
Lightning-generated whistler waves	Dipolar region close to Earth	Associated with lightning occurrence Scatter radiation-belt electrons into atmosphere	100–10,000 Hz
Kelvin–Helmholtz oscillations	Magnetopause	Driven by magnetosheath flow Transport plasma from magnetosheath into magnetosphere Transport momentum into magnetosphere to produce magnetospheric convection Produce ULF waves in dipolar region	80–700 s
Magnetosonic waves (equatorial noise)	Dipolar region	Driven by ion plasma sheet Energize the electron radiation belt	20–150 Hz
Alfven waves	Throughout the magnetosphere	Initiate electrical currents that couple the motions of plasmas	60–500 s