Sources

Amplitude

frequency

Characteristics

HFGW in Quintessence inflationary models

Random background

HFGW in some string theory scenarios

Random background

Solar Plasma

On the Earth

High energy particles, e.g. Fermi Ring

On the center the frequency depends upon the rotational frequency of particles in the Fermi Ring

Stanford Linear Accelerator

On the collision center, the frequency depends upon the self-energy and the Lorentz factor of high energy e⁺e⁻ beams

LHC-Large Hadron collider

Spectra of high energy gravitons

Nano-piezo electric crystal array, with size of about 100 nanometers

On the wave zone with an effective cross section of or less than 0.01 meters squared, for gravitational radiation