Characteristics of a Dipole and a Loop Antenna for Plasma Waves Observed by the S-310JA-1 Rocket

Abstract

Among VLF wave phenomena observed by the S-310JA-1 rocket, what is thought as a kind of plasma wave phenomenon has been investigated in detail. The phenomenon is characteristic in that its frequency was spin-modulated and it appeared once during one spin period, and it was detected with a ferrite core loop antenna as well as with a 28 m dipole antenna. It is concluded that this phenomenon may be an electrostatic wave with a wave length of the order of 10 cm. The loop antenna is considered to have worked as an electric sensor by the whip antenna effect, when the phenomenon was detected. It is also found that the 28 m dipole antenna is a very short antenna with an effective length of ～1 mm for the above plasma wave. Therefore, the phenomenon can be quantitatively understood from these characteristics of the antennas