On the possibility of detecting synchrotron radiation from electrons in the Van Allen belts

It is known that a moving charged particle can be trapped in the earth's magnetic field indefinitely. Indeed, high-speed charged particles, presumably electrons, have recently been observed in nature by United States satellites and lunar probes. These electrons are relativistic and should emit radiofrequency wide-band noise similar to that observed in synchrotrons even as high as optical frequencies. Most of this energy is unable to reach the earth's surface because of reflection from the intervening ionosphere. A small fraction of this energy, however, exists at VHF capable of passing down through the ionosphere. It would be desirable to conduct an experimental search for this radiation in order to learn more about the electron energies that exist and to allow observation of the Van Allen belt as a function of time.